Design Methodology of Diaphragm - CUREE · PDF fileDesign Methodology of Diaphragm J. Daniel...

2003

CUREE Publication No. W-27

Earthquake Hazard Mitigation of Woodframe ConstructionFunded by the Federal Emergency Management Agency through a Hazard Mitigation Grant Program

award administered by the California Governor’s Office of Emergency ServicesCUREE

the CUREE-Caltech Woodframe Project

Design Methodology of Diaphragm

J. Daniel DolanDavid M. CarradineJames Wescott Bott

W. Samuel Easterling

The CUREE-Caltech Woodframe Project is funded by the Federal Emergency Management Agency(FEMA) through a Hazard Mitigation Grant Program award administered by the CaliforniaGovernor’s Office of Emergency Services (OES) and is supported by non-Federal sources fromindustry, academia, and state and local government. California Institute of Technology (Caltech)is the prime contractor to OES. The Consortium of Universities for Research in EarthquakeEngineering (CUREE) organizes and carries out under subcontract to Caltech the tasks involv-ing other universities, practicing engineers, and industry.

the CUREE-Caltech Woodframe Project

CUREE

Disclaimer

The information in this publication is presented as apublic service by California Institute of Technology andthe Consortium of Universities for Research in EarthquakeEngineering. No liability for the accuracy or adequacy ofthis information is assumed by them, nor by the FederalEmergency Management Agency and the CaliforniaGovernor’s Office of Emergency Services, which providefunding for this project.

CUREe

CUREEConsortium of Universities for Research in Earthquake Engineering

1301 S. 46th St.Richmond, CA 94804-4698

tel.: 510-231-9557 fax: 510-231-5664e-mail: [email protected] website: www.curee.org

Design Methodology of Diaphragms

CUREE Publication No. W-27

2003

J. Daniel DolanDavid M. Carradine

Washington State University

James Wescott BottW. Samuel Easterling

Virginia Polytechnic Institute and State University

ISBN 1-931995-20-6

First Printing: July 2003

Printed in the United States of America

Published byConsortium of Universities for Research in Earthquake Engineering (CUREE)1301 S. 46th Street, Richmond, CA 94804-4698www.curee.org (CUREE Worldwide Web site)

CUREE

Preface | iii

Preface The CUREE-Caltech Woodframe Project originated in the need for a combined research and implementation project to improve the seismic performance of woodframe buildings, a need which was brought to light by the January 17, 1994 Northridge, California Earthquake in the Los Angeles metropolitan region. Damage to woodframe construction predominated in all three basic categories of earthquake loss in that disaster:

Casualties: 24 of the 25 fatalities in the Northridge Earthquake that were caused by building damage occurred in woodframe buildings (1);

Property Loss: Half or more of the $40 billion in property damage was due to damage to woodframe construction (2);

Functionality: 48,000 housing units, almost all of them in woodframe buildings, were rendered uninhabitable by the earthquake (3).

Woodframe construction represents one of society’s largest investments in the built environment, and the common woodframe house is usually an individual’s largest single asset. In California, 99% of all residences are of woodframe construction, and even considering occupancies other than residential, such as commercial and industrial uses, 96% of all buildings in Los Angeles County are built of wood. In other regions of the country, woodframe construction is still extremely prevalent, constituting, for example, 89% of all buildings in Memphis, Tennessee and 87% in Wichita, Kansas, with "the general range of the fraction of wood structures to total structures...between 80% and 90% in all regions of the US….” (4). Funding for the Woodframe Project is provided primarily by the Federal Emergency Management Agency (FEMA) under the Stafford Act (Public Law 93-288). The federal funding comes to the project through a California Governor’s Office of Emergency Services (OES) Hazard Mitigation Grant Program award to the California Institute of Technology (Caltech). The Project Manager is Professor John Hall of Caltech. The Consortium of Universities for Research in Earthquake Engineering (CUREE), as subcontractor to Caltech, with Robert Reitherman as Project Director, manages the subcontracted work to various universities, along with the work of consulting engineers, government agencies, trade groups, and others. CUREE is a non-profit corporation devoted to the advancement of earthquake engineering research, education, and implementation. Cost-sharing contributions to the Project come from a large number of practicing engineers, universities, companies, local and state agencies, and others. The project has five main Elements, which together with a management element are designed to make the engineering of woodframe buildings more scientific and their construction technology more efficient. The project’s Elements and their managers are:

1. Testing and Analysis: Prof. André Filiatrault, University of California, San Diego, Manager; Prof. Frieder Seible and Prof. Chia-Ming Uang, Assistant Managers

2. Field Investigations: Prof. G. G. Schierle, University of Southern California, Manager 3. Building Codes and Standards: Kelly Cobeen, GFDS Engineers, Manager; John Coil and James

Russell, Assistant Managers 4. Economic Aspects: Tom Tobin, Tobin Associates, Manager 5. Education and Outreach: Jill Andrews, Southern California Earthquake Center, Manager

iv | Design Methodology of Diaphragms

The Testing and Analysis Element of the CUREE-Caltech Woodframe Project consists of 23 different investigations carried out by 16 different organizations (13 universities, three consulting engineering firms). This tabulation includes an independent but closely coordinated project conducted at the University of British Columbia under separate funding than that which the Federal Emergency Management Agency (FEMA) has provided to the Woodframe Project. Approximately half the total $6.9 million budget of the CUREE-Caltech Woodframe Project is devoted to its Testing and Analysis tasks, which is the primary source of new knowledge developed in the Project.

Woodframe Project Testing and Analysis Investigations Task # Investigator Topic

Project-Wide Topics and System-level Experiments 1.1.1 André Filiatrault, UC San Diego

Kelly Cobeen, GFDS Engineers Two-Story House (testing, analysis) Two-Story House (design)

1.1.2 Khalid Mosalam, Stephen Mahin, UC Berkeley Bret Lizundia, Rutherford & Chekene

Three-Story Apt. Building (testing, analysis) Three-Story Apt. Building (design)

1.1.3 Frank Lam et al., U. of British Columbia Multiple Houses (independent project funded separately in Canada with liaison to CUREE-Caltech Project)

1.2 Bryan Folz, UC San Diego International Benchmark (analysis contest) 1.3.1 Chia-Ming Uang, UC San Diego Rate of Loading and Loading Protocol Effects 1.3.2 Helmut Krawinkler, Stanford University Testing Protocol 1.3.3 James Beck, Caltech Dynamic Characteristics

Component-Level Investigations 1.4.1.1 James Mahaney; Wiss, Janney, Elstner Assoc. Anchorage (in-plane wall loads) 1.4.1.2 Yan Xiao, University of Southern California Anchorage (hillside house diaphragm tie-back) 1.4.2 James Dolan, Virginia Polytechnic Institute Diaphragms 1.4.3 Rob Chai, UC Davis Cripple Walls 1.4.4.4 Gerard Pardoen, UC Irvine Shearwalls 1.4.6 Kurt McMullin, San Jose State University Wall Finish Materials (lab testing) 1.4.6 Gregory Deierlein, Stanford University Wall Finish Materials (analysis) 1.4.7 Michael Symans, Washington State University Energy-Dissipating Fluid Dampers 1.4.8.1 Fernando Fonseca, Brigham Young University Nail and Screw Fastener Connections 1.4.8.2 Kenneth Fridley, Washington State University Inter-Story Shear Transfer Connections 1.4.8.3 Gerard Pardoen, UC Irvine Shearwall-Diaphragm Connections

Analytical Investigations 1.5.1 Bryan Folz, UC San Diego Analysis Software Development 1.5.2 Helmut Krawinkler, Stanford University Demand Aspects 1.5.3 David Rosowsky, Oregon State University Reliability of Shearwalls

Preface | v

Not shown in the tabulation is the essential task of managing this element of the Project to keep the numerous investigations on track and to integrate the results. The lead management role for the Testing and Analysis Element has been carried out by Professor André Filiatrault, along with Professor Chia-Ming Uang and Professor Frieder Seible, of the Department of Structural Engineering at the University of California at San Diego. The type of construction that is the subject of the investigation reported in this document is typical “two-by-four” frame construction as developed and commonly built in the United States. (Outside the scope of this Project are the many kinds of construction in which there are one or more timber components, but which cannot be described as having a timber structural system, e.g., the roof of a typical concrete tilt-up building). In contrast to steel, masonry, and concrete construction, woodframe construction is much more commonly built under conventional (i.e., non-engineered) building code provisions. Also notable is the fact that even in the case of engineered wood buildings, structural engineering analysis and design procedures, as well as building code requirements, are more based on traditional practice and experience than on precise methods founded on a well-established engineering rationale. Dangerous damage to US woodframe construction has been rare, but there is still considerable room for improvement. To increase the effectiveness of earthquake-resistant design and construction with regard to woodframe construction, two primary aims of the Project are:

1. Make the design and analysis more scientific, i.e., more directly founded on experimentally and theoretically validated engineering methods and more precise in the resulting quantitative results.

2. Make the construction more efficient, i.e., reduce construction or other costs where possible,

increasing seismic performance while respecting the practical aspects associated with this type of construction and its associated decentralized building construction industry.

The initial planning for the Testing and Analysis tasks evolved from a workshop that was primarily devoted to obtaining input from practitioners (engineers, building code officials, architects, builders) concerning questions to which they need answers if they are to implement practical ways of reducing earthquake losses in their work. (Frieder Seible, André Filiatrault, and Chia-Ming Uang, Proceedings of the Invitational Workshop on Seismic Testing, Analysis and Design of Woodframe Construction, CUREE Publication No. W-01, 1999.) As the Testing and Analysis tasks reported in this CUREE report series were undertaken, each was assigned a designated role in providing results that would support the development of improved codes and standards, engineering procedures, or construction practices, thus completing the circle back to practitioners. The other elements of the Project essential to that overall process are briefly described below. To readers unfamiliar with structural engineering research based on laboratory work, the term “testing” may have a too narrow a connotation. Only in limited cases did investigations carried out in this Project “put to the test” a particular code provision or construction feature to see if it “passed the test.” That narrow usage of “testing” is more applicable to the certification of specific models and brands of products to declare their acceptability under a particular product standard. In this Project, more commonly the experimentation produced a range of results that are used to calibrate analytical models, so that relatively expensive laboratory research can be applicable to a wider array of conditions than the single example that was subjected to simulated earthquake loading. To a non-engineering bystander, a “failure” or “unacceptable damage” in a specimen is in fact an instance of successful experimentation if it provides a valid set of data that builds up the basis for quantitatively predicting how wood components and systems of a wide variety will perform under real earthquakes. Experimentation has also been conducted to improve the starting point for this kind of research: To better define what specific kinds of simulation in the laboratory best represent the real conditions of actual buildings subjected to earthquakes, and to develop protocols that ensure data are produced that serve the analytical needs of researchers and design engineers.

vi | Design Methodology of Diaphragms

Notes (1) EQE International and the Governor’s Office of Emergency Services, The Northridge Earthquake of January

17, 1994: Report of Data Collection and Analysis, Part A, p. 5-18 (Sacramento, CA: Office of Emergency Services, 1995).

(2) Charles Kircher, Robert Reitherman, Robert Whitman, and Christopher Arnold, “Estimation of Earthquake

Losses to Buildings,” Earthquake Spectra, Vol. 13, No. 4, November 1997, p. 714, and Robert Reitherman, “Overview of the Northridge Earthquake,” Proceedings of the NEHRP Conference and Workshop on Research on the Northridge, California Earthquake of January 17, 1994, Vol. I, p. I-1 (Richmond, CA: California Universities for Research in Earthquake Engineering, 1998).

(3) Jeanne B. Perkins, John Boatwright, and Ben Chaqui, “Housing Damage and Resulting Shelter Needs: Model

Testing and Refinement Using Northridge Data,” Proceedings of the NEHRP Conference and Workshop on Research on the Northridge, California Earthquake of January 17, 1994, Vol. IV, p. IV-135 (Richmond, CA: California Universities for Research in Earthquake Engineering, 1998).

(4) Ajay Malik, Estimating Building Stocks for Earthquake Mitigation and Recovery Planning, Cornell Institute for

Social and Economic Research, 1995.

Acknowledgements | vii

Acknowledgements

Acknowledgments for the financial support for this project are extended to the

Consortium of Universities for Research in Earthquake Engineering (CUREE). The project was

funded as part of the CUREE-Caltech Woodframe Project (Earthquake Hazard Mitigation of

Woodframe Construction), under a grant administered by the California Office of Emergency

Services and funded by the Federal Emergency Management Agency. Acknowledgements for

support of the project through in-kind donations are also extended to ITW Foamseal, Inc. for the

donation of the foam adhesive, Sierra Pacific Industries and Hanel Lumber for donation of the

floor joists used in construction of the diaphragms, and Senco, inc. and the International Staple

and Nail Tool Association (ISANTA) for the donation of the nails used in the project.

Acknowledgements are also extended to the coordination provided by Professor John

Hall of the California Institute of Technology and Robert Reitherman, Executive Director of the

Consortium of Universities for Research in Earthquake Engineering. Finally, acknowledgements

are extended to Kelly Cobeen, James Russell and John Coil for the technical advice and guidance

provided during the execution of this testing program.

viii | Design Methodology of Diaphragms

Table of Contents Page

Acknowledgements....................................................................................................................... vii Table of Contents......................................................................................................................... viii List of Figures ................................................................................................................................. x List of Tables ................................................................................................................................. xi Abstract ........................................................................................................................................ xiii Chapter 1 - Introduction...................................................................................................................1

1.1 Introduction....................................................................................................................1 1.2 Objectives and Scope of Research .................................................................................5

Chapter 2 - Literature Review..........................................................................................................7 2.1 Introduction....................................................................................................................7 2.2 Early Testing ..................................................................................................................7 2.3 Dynamic Testing ..........................................................................................................10 2.4 Similar Diaphragms .....................................................................................................12 2.5 Summary ......................................................................................................................15

Chapter 3 - Materials and Methods................................................................................................17 3.1 Scope of Testing .........................................................................................................17 3.2 Test Apparatus .............................................................................................................17 3.3 Diaphragm Construction..............................................................................................24 3.4 Test Parameters ............................................................................................................29 3.5 Instrumentation ............................................................................................................39 3.6 Test Protocol ................................................................................................................44 3.7 Stiffness Analysis.........................................................................................................45

3.7.1 Global Stiffness.............................................................................................46 3.7.2 Shear Stiffness ..............................................................................................47 3.7.3 Bending Stiffness ..........................................................................................49

Chapter 4 - Results and Discussion ...............................................................................................51 4.1 Introduction..................................................................................................................51 4.2 Specimen Test Orientations .........................................................................................52 4.3 Moisture Content and Density Analysis ......................................................................52 4.4 Nail Bending Test Results ...........................................................................................54 4.5 Parameter Effects on Diaphragm Stiffness ..................................................................55

4.5.1 Introduction...................................................................................................55 4.5.2 Effects of Blocking .......................................................................................57 4.5.3 Effects of Adhesives .....................................................................................60 4.5.4 Effects of Center Openings ...........................................................................63 4.5.5 Effects of Corner Openings...........................................................................66 4.5.6 Effects of Chords ..........................................................................................70 4.5.7 Effects of Walls.............................................................................................73

4.6 Diaphragm Strength Results.......................................................................................77 4.7 Conclusions ................................................................................................................78

Chapter 5 - Summary and Conclusions..........................................................................................79 5.1 Summary ......................................................................................................................79

Table of Contents | ix

5.2 Conclusions..................................................................................................................80 References......................................................................................................................................83 Appendix A: Effects of Blocking on Diaphragm Cyclic Stiffness ................................................85

A.1 Introduction .................................................................................................................85 A.2 Comparisons of Blocking Effects ...............................................................................85

Appendix B: Effects of Adhesives on Diaphragm Cyclic Stiffness ..............................................93 B.1 Introduction .................................................................................................................93 B.2 Comparison of Adhesive Effects.................................................................................93

Appendix C: Effects of Center Openings on Diaphragm Cyclic Stiffness ..................................101 C.1 Introduction ...............................................................................................................101 C.2 Comparison of Center Opening Effects ....................................................................101

Appendix D: Effects of Corner Openings on Diaphragm Cyclic Stiffness..................................109 D.1 Introduction ...............................................................................................................109 D.2 Comparison of Corner Opening Effects....................................................................109

Appendix E: Effects of Chords on Diaphragm Cyclic Stiffness..................................................119 E.1 Introduction ...............................................................................................................119 E.2 Comparison of Chord Effects ....................................................................................119

Appendix F: Effects of Walls on Diaphragm Cyclic Stiffness ....................................................127 F.1 Introduction................................................................................................................127 F.2 Comparison of Wall Effects ......................................................................................127

Appendix G: Moisture Content and Density Data .......................................................................137 G.1 Introduction ...............................................................................................................137

x | Design Methodology of Diaphragms

List of Figures Page

Figure 1.1 Cross-Section of a Typical Wood Framed Floor ............................................................2 Figure 1.2 Deep Beam Analogy.......................................................................................................4 Figure 3.1 Triangular Reaction Frame ...........................................................................................19 Figure 3.2 Load Frame, Actuator Connection, and Load Distribution Beam................................20 Figure 3.3 Basic Test Apparatus and Configuration......................................................................21 Figure 3.4 (a) Triangular Reaction Frame Plan View Schematic ..................................................22 Figure 3.4 (b) Elevation View of Triangular Reaction Frame .......................................................22 Figure 3.5 Partial Section of Diaphragm Test Apparatus (for specimens loaded parallel to the

joists) .............................................................................................................................23 Figure 3.6 Rim-Joist Splice for 10 x 40 ft. Specimens (typical both sides)...................................25 Figure 3.7 Basic Specimen Sizes / Orientations ...........................................................................26 Figure 3.7 (a) 16’ x 20’ Specimen .................................................................................................26 Figure 3.7 (b) 20’ x 16’ Specimen .................................................................................................26 Figure 3.7 (c) 10’ x 40’ Specimen .................................................................................................27 Figure 3.8 Fully Sheathed 10 x 40 ft. Specimen............................................................................28 Figure 3.9 Corner Sheathing Opening ...........................................................................................30 Figure 3.10 Center Sheathing Opening..........................................................................................31 Figure 3.11 Test Configuration with Rim-Joists (and corner opening) .........................................33 Figure 3.12 Test Configuration without Rim-Joists ......................................................................33 Figure 3.13 Test Configuration with Walls ...................................................................................35 Figure 3.14 Wall Lifting Davits .....................................................................................................36 Figure 3.14 (a) Walls Lowered and Attached ................................................................................36 Figure 3.14 (b) Walls Unfastened and Raised ...............................................................................36 Figure 3.15 10 x 40 ft Specimen with Walls and Wall-Braces......................................................36 Figure 3.16 Application of Sprayed Foam Adhesive.....................................................................38 Figure 3.17 Foam Adhesive Shown After Removal of a Sheathing Panel ....................................38 Figure 3.18 Instrumentation Plan for 16’ x 20’ Specimen.............................................................41 Figure 3.19 Instrumentation Plan for 20’ x 16’ Specimen.............................................................42 Figure 3.20 Instrumentation Plan for 10’ x 40’ Specimen.............................................................43 Figure 3.21 LVDT’s and Mounting Bracket..................................................................................44 Figure 3.22 Global Deflections of Diaphragm (Fischer et al., 2001).............................................46 Figure 3.23 Global Load-Deflection Hysteretic Curves Illustrating the Cyclic Stiffness Variable,

Kglobal ..........................................................................................................................47 Figure 3.24 Assumed Shear Deformation Pattern for Diaphragms (Fischer et al., 2001) .............48

List of Tables | xi

List of Tables Page

Table 4.1 Average Moisture Content and Density from Sample Analysis ....................................53 Table 4.2 Average Moisture Content from Moisture Meter Readings ..........................................54 Table 4.3 Average Bending Yield Moments for Nails ..................................................................54 Table 4.4 Baseline Cyclic Stiffness for Fully-Sheathed, Nailed, Unblocked Diaphragms with no

Walls or Chords.............................................................................................................55 Table 4.5 Average Baseline Cyclic Stiffness for Fully-Sheathed, Nailed, Unblocked Diaphragms

with no Walls or Chords for Matched Pairs of Diaphragms .........................................56 Table 4.6 Cyclic Stiffness Comparisons for Blocked and Unblocked Configurations..................59 Table 4.7 Cyclic Comparisons for Floor Diaphragms with and without Adhesive .......................61 Table 4.8 Cyclic Stiffness Comparisons for Floor Diaphragms with and without Center

Openings........................................................................................................................65 Table 4.9 Cyclic Stiffness Comparisons for Floor Diaphragms with and without Corner

Openings........................................................................................................................68 Table 4.10 Cyclic Stiffness Comparisons for Floor Diaphragms with and without Chords..........72 Table 4.11 Cyclic Stiffness Comparisons for Floor Diaphragms with and without Walls............76 Table A.1 Cyclic Stiffness Comparisons for Blocked and Unblocked Configurations for

Specimen 2 ....................................................................................................................85 Table A.2 Cyclic Stiffness Comparisons for Blocked and Unblocked Configurations for

Specimen 3 ....................................................................................................................88 Table A.3 Cyclic Stiffness Comparisons for Blocked and Unblocked Configurations for

Specimen 4 ....................................................................................................................89 Table A.4 Averaged Cyclic Stiffness Comparisons for Blocked and Unblocked Configurations

for Specimens 3 and 4 ...................................................................................................91 Table B.1 Cyclic Stiffness Comparisons for Specimen 1 with and without Adhesive..................93 Table B.2 Cyclic Stiffness Comparisons for Specimen 2 with and without Adhesive..................94 Table B.3 Cyclic Stiffness Comparisons for Specimen 3 with and without Adhesive..................97 Table B.4 Cyclic Stiffness Comparisons for Specimen 4 with and without Adhesive..................98 Table B.5 Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without

Adhesive........................................................................................................................99 Table B.6 Averaged Cyclic Stiffness Comparisons for Specimens 3 and 4 with and without

Adhesive......................................................................................................................100 Table C.1 Cyclic Stiffness Comparisons for Specimen 1 with and without Center Openings....102 Table C.2 Cyclic Stiffness Comparisons for Specimen 2 with and without Center Openings ....103 Table C.3 Cyclic Stiffness Comparisons for Specimen 3 with and without Center Openings....104 Table C.4 Cyclic Stiffness Comparisons for Specimen 4 with and without Center Openings....105 Table C.5 Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without

Center Openings ..........................................................................................................106 Table C.6 Averaged Cyclic Stiffness Comparisons for Specimens 3 and 4 with and without

Center Openings ..........................................................................................................107 Table D.1 Cyclic Stiffness Comparisons for Specimen 1 with and without Corner Openings ...110 Table D.2 Cyclic Stiffness Comparisons for Specimen 2 with and without Corner Openings ...111 Table D.3 Cyclic Stiffness Comparisons for Specimen 3 with and without Corner Openings ...113 Table D.4 Cyclic Stiffness Comparisons for Specimen 4 with and without Corner Openings ...114

xii | Design Methodology of Diaphragms

Table D.5 Cyclic Stiffness Comparisons for Specimen 5 with and without Corner Openings ...115 Table D.6 Cyclic Stiffness Comparisons for Specimen 6 with and without Corner Openings ...115 Table D.7 Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without

Corner Openings ..............................................................................................................116 Table D.8 Averaged Cyclic Stiffness Comparisons for Specimens 3 and 4 with and without

Corner Openings..............................................................................................................117 Table D.9 Averaged Cyclic Stiffness Comparisons for Specimens 5 and 6 with and without

Corner Openings ..............................................................................................................118 Table E.1 Cyclic Stiffness Comparisons for Specimen 1 with and without Chords ...................120 Table E.2 Cyclic Stiffness Comparisons for Specimen 2 with and without Chords ...................121 Table E.3 Cyclic Stiffness Comparisons for Specimen 5 with and without Chords ...................124 Table E.4 Cyclic Stiffness Comparisons for Specimen 6 with and without Chords ...................124 Table E.5 Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without

Chords ..............................................................................................................................125 Table E.6 Averaged Cyclic Stiffness Comparisons for Specimens 5 and 6 with and without

Chords ..............................................................................................................................126 Table F.1 Cyclic Stiffness Comparisons for Specimen 1 with and without Walls ......................128 Table F.2 Cyclic Stiffness Comparisons for Specimen 2 with and without Walls ......................129 Table F.3 Cyclic Stiffness Comparisons for Specimen 3 with and without Walls ......................131 Table F.4 Cyclic Stiffness Comparisons for Specimen 4 with and without Walls ......................132 Table F.5 Cyclic Stiffness Comparisons for Specimen 5 with and without Walls ......................133 Table F.6 Cyclic Stiffness Comparisons for Specimen 6 with and without Walls ......................133 Table F.7 Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without

Walls ................................................................................................................................134 Table F.8 Averaged Cyclic Stiffness Comparisons for Specimens 3 and 4 with and without

Walls ................................................................................................................................135 Table F.9 Averaged Cyclic Stiffness Comparisons for Specimens 5 and 6 with and without

Corner Openings ..............................................................................................................136 Table G.1 Specimen 1 Joist Sample Data....................................................................................138 Table G.2 Specimen 1 Daily Moisture Meter Readings ..............................................................139 Table G.3 Specimen 1 Plywood Sample Data .............................................................................140 Table G.4 Specimen 2 Joist Sample Data....................................................................................141 Table G.5 Specimen 2 Daily Moisture Meter Readings ..............................................................142 Table G.6 Specimen 3 Joist Sample Data....................................................................................143 Table G.7 Specimen 3 Daily Moisture Meter Readings ..............................................................144 Table G.8 Specimen 4 Joist Sample Data....................................................................................145 Table G.9 Specimen 4 Daily Moisture Meter Readings ..............................................................146 Table G.10 Specimen 5 Joist Sample Data..................................................................................147 Table G.11 Specimen 6 Joist Sample Data..................................................................................148

Abstract | xiii

Abstract

Six diaphragms were tested using cyclic displacements to determine the effect various

construction details have on stiffness. Three diaphragm aspect ratios were investigated, 16 x 20

ft (4:5), 20 x 16 ft (5:4), and 10 x 40 ft (1:4). Two loading cases were investigated, Case 1 with

the load oriented parallel to the joists and perpendicular to the continuous the continuous joint in

the sheathing, and Case 2, with the load oriented perpendicular to the joists and parallel to the

sheathing continuous joints in the sheathing. Construction details investigated include blocking,

adhesives, presence of designated chord members, openings (center and corner), and walls on top

of the diaphragm.

Results show that blocking is the most effective method of stiffening the diaphragm and

adhesives augment their effect. There is significant ability to resist loads through bending action,

but the presence of designated chord members significantly increases the bending stiffness. The

effect of openings on shear stiffness is proportional to the size of the opening, but not necessarily

linearly proportional to the size of the opening. Finally, the effect of walls on top of the

diaphragm on the bending stiffness of the diaphragm is significant if they are attached well.

xiv | Design Methodology of Diaphragms

Introduction | 1

Chapter 1 - Introduction

1.1 Introduction

Modern structural engineering frequently involves sheathed construction, a load

resistance method exemplified in various structural elements by many combinations of suitable

materials. A common form of sheathed construction, the diaphragm, is a thin, usually planar

system of sheathing and frame members, intended to withstand considerable in-plane forces.

When referring to residential housing, everyday plywood construction typically comes to mind.

Most apparent examples of diaphragms are walls, upper-story floors, and roofs of

everyday structures such as residential houses, office buildings, and warehouses. Though similar

in function, wall diaphragms, called shear walls, require different consideration for design and

analysis, and thus fall outside of the scope of this investigation. Roofs and above-grade floors,

when designed as such, fall into the classification as true diaphragms. Typical combinations of

materials employed are wood sheathing on wood frame, metal sheathing on wood frame, metal

sheathing on metal frame, wood sheathing on metal frame, and variations using concrete,

structural insulation panels, and other construction materials. This research project is limited to

wood-framed and plywood-sheathed floor diaphragms typical in residential housing.

The common floor and roof diaphragm serves dual purposes by supporting vertical forces

(from loads such as furniture, people, snow, uplift, and its own dead load) and by transmitting

horizontal forces (from wind pressure or earthquake accelerations) to the supporting shear walls.

Floors and roofs are inherently able to carry gravitational loads due to the typical design by

which appropriately spaced framing members are covered with sheathing and fastened together.

Joists and rafters, the common framing members of floors and roofs, respectively, are oriented to

2 | Design Methodology of Diaphragms

maximize the moment of inertia for resistance to flexure. Thus, a 2x10 floor joist would be

installed such that the nominal ten-inch side is vertical. The sheathing spans the distance

between and transmits loads to the framing members below. The framing members then

distribute the loads proportionally to supporting walls or posts. Also, when adequately fastened

together, the sheathing and framing can produce a flexurally efficient composite section.

Resistance to vertical forces, though a primary consideration in design and construction of floors

and roofs, is not the subject of this study.

Sheathing

Wood Floor Joists

Figure 1.1 Cross-Section of a Typical Wood Framed Floor

Horizontal forces applied to diaphragms are almost exclusively from wind and

earthquakes. Wind pressure on the exterior walls is transmitted proportionately along the edge of

a diaphragm as a uniform load. In the case of wind-loaded floors, connections with the top plate

of the wall below and the sill plate of the wall above provide paths for load transfer. When

Introduction | 3

subjected to earthquake accelerations, its own inertia, or resistance to motion, and that of

attached walls or partitions causes horizontal loading of a diaphragm. Diaphragms are usually

more than capable of withstanding these loadings due to high in-plane shear capacity. Sheathing

material itself exhibits considerable in-plane shear strength. Hence, the reason a sheet of

plywood is much more rigid when loaded along the thin edge (in-plane) as opposed to the large

flat surface (out of plane). Accordingly, a low aspect ratio system of sheathing panels, properly

fastened together end-to-end along the edges, has an effective shear capacity. The fact that the

primary element in diaphragm construction, the sheathing, is so relatively thin, in most cases, that

it provides an efficient and lightweight means of resisting in-plane loads.

Resistance to these in-plane loads through diaphragm action may be accurately compared

to the loading of a deep wide-flange beam, as illustrated in Figure 1.2. The shear walls of a

structure are analogous to the simple supports of the beam and provide the reaction against the

forces transmitted through the diaphragm. The inter-connected sheathing panels behave like the

web of the beam to resist the shear component of in-plane loads. And, the extreme edges of the

sheathing and/or the boundary members running perpendicular to the direction of the loads

simulate the flanges of the beam by carrying the tension and compression from the flexural

reaction to the loads.


Web

Flange

Figure 1.2 Deep Beam Analogy

The behavior of floor and roof diaphragms has become an important issue with respect to

lateral stiffness and deflection. It has been noted that there is seldom a problem with the strength

of diaphragms, because failures are predominantly associated with the connections between a

diaphragm and supporting walls. Though the occurrence of actual failures is rare, diaphragms

have sometimes been a controlling factor in the overall failure of structures during seismic events

(Dolan 1999). Poor understanding of diaphragm behavior has spurred the interest of researchers

to formulate more accurate methods of analysis and design similar to methods already employed

in the design of cold-formed steel diaphragms.

Introduction | 5

1.2 Objective and Scope of Research

The objective of this study is to develop an accurate method to determine shear stiffness

of wood diaphragms based on the formulas currently used in the Cold-Formed Steel Design

Manual, and provide an improved method of predicting diaphragm deflections. The capability to

accurately calculate diaphragm stiffness will enhance the safety and economy of design and

construction of wood diaphragms. Current systems are not able to incorporate many factors such

as sheathing openings, absence of chords, use of sheathing adhesive, and non-rectangular shapes.

This objective is accomplished by means of a series of experimental tests on full-scale

diaphragms. The testing procedures are discussed in detail in Chapter III.


Literature Review | 7

Chapter 2 – Literature Review

2.1 Introduction

The wood engineering community is constantly striving to enhance the designability,

performance and economy of wood structures. In particular, the behavior of floor and roof

diaphragms has become an important issue with respect to lateral stiffness and deflection. It has

been noted that there is seldom a problem with the strength of diaphragms, because failures are

predominantly associated with the connections between a diaphragm and supporting walls.

Though the occurrence of actual failures is rare, diaphragms have sometimes been a controlling

factor in the overall failure of structures during seismic events. Poor understanding of diaphragm

behavior has spurred the interest of researchers to formulate more accurate methods of analysis

and design similar to methods already employed in the design of cold-formed steel diaphragms.

The objective of this report is to review major studies in this field performed on both a

theoretical and experimental basis. Sporadic since the 1950’s, most of the testing of wood

diaphragms has occurred at the facilities of the Douglas Fir Plywood Association (DFPA),

American Plywood Association (APA), Oregon State University, Oregon Forest Products

Laboratory, Washington State University, and West Virginia University.

2.2 Early Testing

The DFPA sponsored some early tests in diaphragm behavior. Countryman (1952)

describes lateral tests on plywood-sheathed diaphragms. Four specimens, 12 x 40 ft. and 20 x 40

ft., and six one-quarter scale models, 5 x 10 ft., were tested by monotonic loading at fifth-points.

The specimens had varying parameters such as blocking, openings, staggered panels, gluing,

plywood thickness, nail size, and boundary nailing patterns. Stiffness of the diaphragms was


calculated from measured lateral deflection in the middle of the lower chord and applied load.

Shear deformation, and not flexural deformation was determined to be the predominant form of

deflection. Load versus deflection plots show that the actual deflection was consistently higher

than calculated values using existing equations. It was found that diaphragms behave like a

horizontal girder with a shear-resistant web. Chord members resist the flexural tension and

compression stresses, while the web resists the shear. Strength and stiffness of the specimens

was found to be primarily dependent on the strength of the nailed plywood-to-frame connections.

Due to over conservative design codes, the DFPA pursued further studies in diaphragm

action. Countryman and Colbenson (1954) report on tests of fifteen full-scale diaphragms,

conducted to better understand the strength effects from:

1. Omission of blocking 2. Panel arrangement 3. Nailing schedules 4. Span-thickness combinations 5. Length-width ratio 6. Seasoning of frame lumber 7. Use of three inch lumber 8. Cut-in blocking for chords 9. Load application perpendicular to joists 10. Screwed cleats in lieu of blocking

All 24 x 24 ft. specimens were monotonically loaded with four equal lateral forces at fifth points

of the span and deflections were measured from the middle of the unloaded chord. Plywood

thickness and nailing schedule, along with blocking to a lesser degree, were found to be the

predominant factors in determining strength and stiffness. Ultimate applied shears ranged from

733 to 2530 plf, while ultimate deflections occurred from 0.52 to 3.2 in. For blocked

diaphragms, the measured deflections are consistent with a formula produced as a result of the

DFPA Report No. 55 (Countryman 1952) with an average error of 15%.


In conjunction with the research described above, the DFPA also sponsored tests at the

Oregon Forest Products Laboratory. The two 20 x 60 ft. roof diaphragms tested, were constructed

with the lightest framing and plywood thickness permissible at that time for a roof of this size

(Stillinger and Countryman 1953). The 2 x 10 joists were framed at 24 in. o.c. and sheathed with

3/8-in. thick plywood. One of diaphragms was blocked along the panel edges. The diaphragms

were loaded monotonically by hydraulic jacks at the fifth points. The 3/8-in. thick plywood was

found to be adequate, though not as strong as specimens with thicker plywood. The lightweight

framing system performed adequately enough to be considered in construction methods. Lastly,

it was found that for unblocked diaphragms, no special boundary nailing detail was required

regardless of the reduced strength.

The APA became interested in lateral shear testing of diaphragms not composed of

Douglas Fir plywood. Tissell (1966) validated the DFPA tests from 1955 as well as going on to

test diaphragms of other various species of wood that were becoming popular in construction.

Nineteen full-scale 16 x 48 ft. diaphragms were tested. Plywood characteristics, sheathing-to-

framing connections, nail types, and framing member types were varied in the tests. Monotonic

loading from 16 hydraulic jacks at 3 ft. on center was used to approximate a uniform lateral load.

Lateral deflections were measured with dial gages at mid span of the tension chord. The design

shear values were found to be very conservative, with the average ultimate load being 1545 plf

and the average allowable design load being only 420 plf (includes factors of safety). Sheathing

of different species of wood was found to have a small but accountable change in shear strength

and stiffness. However, effects from plywood grade and quality were found to be negligible.

Tissell concluded that shear strength equivalent to that of blocked diaphragms is possible by

stapling tongue-and-groove 2-4-1 plywood. Further, shorter ring-shank nails are permissible as


long as a minimum penetration is attained. Open-web steel joist-framed diaphragms were

slightly stronger than the lumber framed diaphragms. The DFPA design values determined from

the tests previously discussed (Countryman and Colbenson 1954) were found to adequately

conservative.

2.3 Dynamic Testing

GangaRao and Luttrell (1980) explain the efforts at West Virginia University to quantify

shear response of diaphragms with the ultimate goal in preparing accurate analysis models for

future design purposes. Since diaphragms had been mainly studied under static loading

conditions, they propose that stiffness characteristics are an equally critical issue in a correct

estimation of behavior under real-life dynamic loading. Preliminary dynamic results from tests at

West Virginia University were used to derive joint slip and shear deformation response equations

based on dynamic loading. They predicted that damping characteristics with respect to joint slip

are the critical factors needed in order to appropriately describe diaphragm behavior under

dynamic loads.

At the time, Polensek (1979) was the only researcher making attempts at quantifying

damping characteristics for horizontal dynamic loading. His tests of plywood sheathed

diaphragms with six or ten inch joists yielded average damping ratios between 0.07 and 0.11.

However, he considered that the data accumulated had been too varied for an accurate estimation

of the damping ratio. It was apparent, however, that an increase in floor span is directly

proportional to the damping effect.

At West Virginia University, Jewell (1981) performed experimental tests on partial

(cantilever) diaphragms in order to analyze a range of different parameters such as nail spacing,


boundary conditions, connection details, load type, and damping capacity. Three 16 x 24 ft.

diaphragms and six 16 x 16 ft. diaphragms were tested under monotonic, cyclic, and impact loads

in the directions perpendicular and parallel to the joists. Replica diaphragms were also modeled

in the same configurations as flexible composite members in a finite element analysis to

determine any inaccuracy in this theoretical approach. Based on a comparison of the theoretical

and experimental test results, Jewell was able to analyze relationships of plywood behavior, nail

slip, effect of loading, effect of joist hangers, and damping to the stiffness of diaphragms. In

most cases, the finite element approach yielded slightly more conservative results for stiffness

(i.e., predicted deflections were lower than actual), based on the parameters listed above.

Corda (1982) and Roberts (1983) performed additional cantilever diaphragms tests at

West Virginia University in another codependent study involving laboratory testing and finite

element modeling. Corda tested six 16 x 24 ft. specimens cyclically and statically to failure in

order to study local and global in-plane shear stiffness response to variations of blocking,

openings, plywood thickness, corner stiffeners, and framing nail sizes. It is noteworthy that nail

softening after loads up to ±9 kips on some specimens caused a large decrease in stiffness.

Increased plywood thickness (without using longer nails) and corner openings reduced strength

but had little effect on stiffness. Roberts’ theoretical analysis of equivalent models of the

diaphragms tested by Corda, showed some evident discrepancies. Problems with the finite

element analysis program included the limitation to monotonic loading, inaccurate predictions of

panel slip, and the iterative processes of calculation of diaphragm deflection with respect to nail

slip, a bilinear relationship, demanding the modification of results to a nonlinear solution using

the tangent stiffness method. Based on the problems encountered, Roberts suggested that the

limitations imposed on the program user in modeling plywood diaphragms need to be eliminated


by further experimental research into stiffness characteristics of panel slip, plywood layout and

connection, diaphragm openings, and nail slip under cyclic loading.

A recent APA report by Tissell and Elliott (1997) describes diaphragm testing for high

load conditions equivalent to earthquakes accelerations. The primary intent was to formulate

design and construction approaches for these “high-load” diaphragms, which may incorporate

use of two layers of plywood, thicker plywood, or stronger fastener conditions. Ten of the

diaphragms tested were 16 x 48 ft., and the dimensions of an eleventh specimen were changed to

10 x 50 ft. Hydraulic jacks at a spacing of 24 in. o.c. were used to apply a cyclic uniform load

along the long side of the diaphragms. Results show that it is possible to increase shear strength

by increasing the number of fasteners or adding another layer of sheathing in areas of high shear.

This report also notes that plywood panel shear capacity must be checked for “high-load”

diaphragms. Staples were found to be adequate fasteners in lieu of nailed sheathing-to-framing

connections. Along the same lines, field glued joints and a reduced number of nails are adequate

for these diaphragms.

2.4 Similar Diaphragms

The abundant studies of floors comprised of materials other than wood are important in

order to understand general behavior of diaphragms. It is possible that wood diaphragm design

methods may be simplified and accurately rationalized in terms of methods already in use for

other materials. A theoretical study of the behavior of composite steel beam and concrete deck

diaphragms was made by Widjaja (1993) at Virginia Polytechnic Institute and State University.

Similar to many efforts currently in progress for wood diaphragms, the purpose of this study was

to develop an accurate finite element analysis model that predicts diaphragm behavior,


incorporates possible variations of design parameters, and derives design strength equations.

Similarly, experimental cantilever tests on cold-formed steel diaphragms are important in the

design of many steel-frame building roofs and composite floors (during construction, before

concrete). Post-frame diaphragm testing (wood frame and metal sheathing) is also significant in

terms of the more agricultural or shed type buildings.

With sponsorship from NUCOR Research and Development, Hankins (1992) performed

eighteen cantilever diaphragm tests at Virginia Polytechnic Institute and State University to

determine strength and stiffness of cold-formed steel sheathing, 20 and 22 gage thickness

(Vulcraft 1.5B1 deck), welded or bolted to a steel frame. The 16 x 16 ft. specimens were

subjected to monotonic loads. Thirteen diaphragms utilized an 8 ft. span, requiring only one

filler beam. The other five specimens had a filler beam spacing of 4 ft., requiring three filler

beams. Bolt and puddle weld arrangement, used to secure the sheathing, was varied to determine

its effects on diaphragm behavior. Results from the tests indicate that specimens with thicker

gage sheathing have more strength and stiffness. However, even though specimens with smaller

filler beam spacing (three filler beams as opposed to one) had more strength, the diaphragm

stiffness was less in some cases.

Hausmann and Esmay (1977) report the results of tests on twenty-six full size post-frame,

metal-clad diaphragm panels. All specimens were 8 x 16 ft. with rafters at 4 ft. o.c. along the 16

ft. side and purlins at 2 ft. o.c. along the 8 ft. side. Loaded monotonically at the ends of the three

interior rafters, the panels were analyzed for strength and stiffness based on varying parameters

such as framing arrangement, type, number, and metal of fasteners, aluminum or steel sheathing,

and with or without insulation. It was determined that purlins laid flat to the rafters was the more

suitable method of framing. Screw fasteners in the panel valleys increased diaphragm stiffness


and strength, especially for the steel clad specimens. Aluminum panels were more suitable with

nailing, due to a larger cover width for each sheet. Placing insulation between wood-framing and

metal cladding not only reduces diaphragm strength, but also seriously affects stiffness. Fastener

configurations have important and measurable effects on diaphragm behavior.

Anderson and Bundy (1990) performed additional post-frame diaphragm tests to outline

the effects of openings in the sheathing. Fifteen cantilever specimens, 7-2/3 x 12 ft. with two

interior rafters and seven purlins were tested monotonically with varying amounts of sheathing

missing. Diaphragms were constructed with SPF lumber, screw fasteners, and steel sheathing.

Fastener configurations were found to be extremely important for diaphragm stiffness. Openings

in the sheathing at normal intervals caused the specimens to be ineffective as diaphragms. It was

also found that spacing of purlins has little impact on strength or stiffness of the diaphragms.

In addition to the physical testing, there has been a great deal of computer modeling of

post-frame diaphragms for scientific purposes in order to aid designers and validate experimental

results. For example, Wright and Manbeck (1993), among many others, conducted finite element

analyses of post-framed diaphragm panels. Following procedures provided by Woeste and

Townsend (1991), they modeled full size 8 x 12 ft. diaphragms with 2x4 in. purlins at 2 ft. o.c.,

2x6 in. rafters at 3 ft. o.c., and steel cladding secured with 16d nails. The finite element model

was compared to three identical experimental diaphragm tests. The finite element model closely

predicted diaphragm shear strength, but under-estimated shear stiffness by 28%. Results show

that discrepancies arise due to difficulties in modeling nonlinear behavior of fasteners and

intricate load paths between the wood frame and steel sheathing.


2.5 Summary

Horizontal wood diaphragm behavior is a critical element in the design of safe and

economical wood structures in areas of seismic activity and high wind loading. This study of

research performed in this field is important in order to know what characteristics have already

been established and what questions of diaphragm behavior are still unanswered. Horizontal

diaphragm stiffness with respect to adequate connection to shear walls is still a difficult

relationship in wood design. In accordance with Task 1.4.2 of the CUREE-Caltech Woodframe

Project, attempts are being made to devise finite element analysis models and design procedures

equivalent to those for cold-formed steel diaphragms that resolve this problem for wood

diaphragms. Critical to this project are diaphragm stiffness characteristics, a subject that this

review shows a lack of completeness. As a result Task 1.4.2 is aimed at numerical modeling and

full-scale diaphragm tests to provide stiffness guidelines for design under seismic conditions.


Materials and Methods | 17

Chapter 3 – Materials and Methods

3.1 Scope of Testing

Multiple stiffness tests and one test to failure were performed on each of six full-scale

diaphragms at the Thomas M. Brooks Forest Products Center of the Virginia Polytechnic

Institute and State University located in Blacksburg, Virginia. Consortium of Universities for

Research in Earthquake Engineering (CUREE) sponsored the research under its Wood Frame

Project, Task 1.4.2 – Diaphragm Studies.

Diaphragm dimensions of four specimens were 20 ft by 16 ft with varying orientations,

while two high-aspect ratio specimens were 10 ft by 40 ft. Multiple tests on each specimen were

possible due to the small deflections being imposed, allowing an economical means of

incorporating multiple test parameters. Test parameters investigated for effects on diaphragms

stiffness were: 1) corner opening, 2) center opening, 3) fully sheathed, 4) 6-12 nail pattern, 5) 3-

12 nail pattern, 6) with/without chords, 7) with/without walls, 8) with/without blocking, and 9)

with/without foam adhesive. Specimens were subjected to non-destructive, low-amplitude

dynamic-cyclic loading by a computer-controlled hydraulic actuator, while load and deflection

values were being recorded by a computer data acquisition system. The final test on each

specimen, though not a primary focus of this study, was an attempt to cause diaphragm failure.

3.2 Test Apparatus

Diaphragm testing was conducted on an 22 X 50 ft. concrete pad with 42 in. wide by 27

in. tall concrete backwalls along two adjacent sides. The heavily reinforced back-walls have two


7/8 in. diameter anchor bolts embedded in the concrete 2 ft. on center with a 400,000 lb point-

load capacity at a minimum spacing of 6 feet.

A computer controlled hydraulic actuator was mounted horizontally at the midpoint of the

50 ft. backwall. The actuator had a 55 kip capacity with a ± 6 in. stroke, and included a 50 kip

Interface load cell, screwed onto the end of the hydraulic cylinder. Load was transferred from a

ball joint at the end of the actuator, through a pin-connected gusset to a 20 ft. long C6x10.5 steel

channel. The channel, as shown in Figure 3.2, was fastened along the entire width in the center

of the specimen span with 5/8 in. diameter lag screws. In the case where a joist was not located

in the center of the diaphragm, 4x4 blocks are placed under the sheathing to provide a backing

for the lag screws used to attach the load distribution beam.

Offset equal distances (based on dimensions of diaphragm specimens) from the centerline

of the actuator were triangular reaction frames, made from 4 X 6 in. steel tubes welded together.

Each reaction frame was connected to the concrete back-wall with four 7/8 in. diameter anchor

bolts. A one-inch thick end plate was welded to the end of the steel tube of the reaction frame

and was drilled and tapped for a 1¼ in. threaded rod. A two-foot piece of threaded rod screwed

through the plate and into the hollow steel tube to leave the desired length exposed. A shop-

fabricated, full-bridge load cell made of 2 in. diameter steel rod and strain gauges screwed onto

the opposite end of the threaded rod. The load cell had a large hex-nut welded to one end for

connecting to the threaded rod protruding from the triangular reaction frame. Gusset plates were

welded to the opposite end of the threaded rod to provide a pinned connection to the diaphragm

support frame.


Each end of the diaphragm was attached to a 20 ft.-L2x2x¼ steel angle, which was

welded intermittently to the side of a 20 ft.-3 X 5 in. steel tube using lag screws. One end of each

steel tube was pin-connected to the gusset plates of the reaction load cells. This support frame

served the same purpose as shear walls by transmitting loads out of the diaphragm at each end.

These loads were then measured by the load cells of the reaction frames. The support frame

served a secondary purpose, to hold the diaphragm at the proper elevation for concentric loading

from the actuator. Several one-inch diameter PVC pipes were also placed on the concrete under

the specimen to help hold the interior of the specimen at the proper elevation, and to act as

“frictionless” rollers under the joists as load was applied.

Figure 3.1 Triangular Reaction Frame


Figure 3.2 Load Frame, Actuator Connection, and Load Distribution Beam


Figure 3.3 Basic Test Apparatus and Configuration

Steel Channel(C6 x 10.5)

Lag Screws

Concrete Back Wall

See Figure 2.4 for Detail

Fig. 2.5

Load Cell

Actuator

Diaphragm Size and Sheathing Layout Varies

Support Frame 3" x 5" Steel Tube

Triangular Reaction Frame

Load Cell


Load Cell

Steel Tube Frame

Fig. 2.4a

Figure 3.4 a) Triangular Reaction Frame Plan View Schematic

Pinned Connection

Concrete Backwall

Diaphragm Support Frame

Figure 3.4 b) Elevation View of Triangular Reaction Frame


Figure 3.5 Partial Section of Diaphragm Test Apparatus (for specimens loaded parallel to the joists)

2 x 12 Joists @ 16"(Douglas Fir)

2332" T&G Plywood

Sheathing

PVC Pipe Rollers11

4 " φ

Steel Channel (C6X10.5) - Lag Screwed to non-structural blocks

Steel Angle:-Welded to Steel Tube-Lag Screwed to End Joist

3" x 5" Steel Tube

Steel Pipe Roller


3.3 Diaphragm Construction

Of the six, full-scale diaphragm specimens, two were 16 x 20 ft. in dimension and were

loaded parallel to the direction of the joists on the 20 ft. side. Two specimens were 20 x 16 ft. in

dimension, loaded perpendicular to the joists on the 16 ft. side. The last two specimens were 10

x 40 ft. in dimension, loaded parallel to the joists on the 40 ft. side. Resembling the size and

shape of one side of a roof of a typical residential home, these 10 x 40 ft. specimens were

intended to test the envelope of diaphragm performance with respect to aspect ratio.

The diaphragm specimens were framed with Douglas fir 2 x 12 joists spaced at 16 in. o.c.

and nailed with three 16d nails at each end to a 2 x 12 Douglas fir rim joist. In the case of

specimens loaded parallel to the direction of the joists, the bottom of each end joist was attached

to the diaphragm support frames using lag screws as shown in Figure 3.5. Conversely, when

loading was applied perpendicular to the joists, the rim-joists were connected to the support

frames. Since the lumber used is 20 ft in length, the rim joists of the 40 ft. long specimens had to

be spliced in the center with steel plates and bolts as shown in Figure 3.6. Additionally, a wood

sample was taken from each joist of every specimen for moisture content and density analysis.

This information recorded for possible use when evaluating test results, since moisture content

changes in lumber affects fastener performance. Schematic illustrations of the three specimen

configurations, including loading and reaction locations, are illustrated in Figures 3.7a-c. A

photograph of a 10 x 40 ft diaphragm specimen is presented in Figure 3.8.


Figure 3.6 Rim-Joist Splice for 10 x 40 ft. Specimens (typical both sides)


(a) 16’ x 20’ Specimen

(b) 20’ x 16’ Specimen

Figure 3.7 Basic Specimen Sizes / Orientations

20'

Load Applied4'x8'x2332" T&G

Plywood Sheathing

16'

Cut-out shows framing layout below

2 x 12 Joists @ 16"(Douglas Fir)

2 x 4 Blocking(on flat)

2 x 12 Rim-Joist(Douglas Fir)

20'

Load Applied16'


10'

Load

App

lied

4'x8

'x23

32" T

&G

Ply

woo

d S

heat

hing

40'

(c) 1

0’ x

40’

Spe

cim

en

(c

) 10’

x 4

0’ S

peci

men

Figu

re 3

.7

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Figure 3.8 Fully Sheathed 10 x 40 ft. Specimen

The specimens were sheathed with nominal 4 x 8 ft. sheets of 23/32 in. tongue-and-

groove plywood in a staggered panel configuration. Sheets were cut where necessary to fully

complete the panel configuration desired. Sheets were attached to the framing with 10d nails in a

6/12 nail pattern, meaning nails are spaced at 6 in. around the perimeter and at 12 in. on the

interior supports of each sheathing panel. Typical sub-flooring construction adhesive was not

used between the joists and plywood sheathing; however some tests involved the use of sprayed

foam adhesive.


3.4 Test Parameters

The specimens were subjected to a number of different construction variations, including the

multiple combinations thereof. The variations tested were:

1. Sheathing openings – fully sheathed, corner opening, center opening 2. Chord members – with / without rim joist 3. Blocking – with / without 2 x 4 blocking 4. Walls – with / without 4 ft. tall stud-framed walls 5. Sprayed foam adhesive & nails versus nailed only 6. Sheathing nail density – 6/12 versus 3/12 nail pattern

Variations to the basic specimen listed above, are individually discussed in detail in the

following paragraphs.

Openings in the plywood sheathing were intended to simulate common openings in floors

of residential homes for stairways, atriums, and vaulted ceilings. These openings weaken and/or

cause torsional irregularities that can dramatically affect the stiffness of diaphragms. Duplex

(double-headed) 10d nails were used to fasten the sheathing panels that were to be removed from

the specimens in order to simulate openings. The corner opening in all sizes and orientations of

specimens was easily achieved by removing one full 4 x 8 ft sheet of plywood from a corner.

However, the center opening presented more challenges due to the staggered sheathing

configuration and tongue-and-groove plywood. For both orientations of the 16 x 20 ft.

specimens, an 8 x 12 ft. rectangular opening was made by prying the unfastened sheets up in the

center along the tongue-and-groove seam like an “army tent” and lifting them out. Some sheets

had to be cut in half to achieve a rectangular opening. Due to the high aspect ratio of the 10 x 40

ft. specimens, a proportional rectangular opening in the center was not reasonable, since typical

roof and floor diaphragms would not have such an opening. A schematic drawing and


accompanying photograph of the two opening types used in the tests are presented in Figures 3.9

and 3.10.

Figure 3.9 Corner Sheathing Opening

Load Applied


Figure 3.10 Center Sheathing Opening

Load Applied


The chords of a diaphragm are the exterior framing members that are oriented

perpendicular to the direction of loading. They serve to resist bending forces in the diaphragm

while also supporting the extreme edges of the sheathing. In the case of floor diaphragms, the

chords may either be the rim joist or simply the last joist at each end of the floor, depending on

the orientation and direction of loading. Residential roof diaphragms typically do not have a true

rim joist, either at the lower edge along the fascia or at the ridge (unless the fascia board or ridge

beam is considered to be effective). The absence of an effective chord is especially prevalent for

roof systems utilizing metal plate connected trusses.

Though all testing was performed on floor diaphragm specimens, chord effects should be

proportionately the same for roof-like specimens. The effectiveness of the chords was quantified

by running tests with and without the designated chord members (rim joists) in place. Only

specimens that had rim joists for the chords (specimens loaded parallel to the direction of the

joists) were able to be tested in this manner. The rim joists were nailed to the diaphragm at each

joist with three 16d duplex nails. Plywood edges were nailed to the rim joist with 10d duplex

nails at 6 in. o.c. Duplex nails were used for easy removal of the rim joists between different test

specimen configurations. One of the diaphragm specimens is shown in the conditions of having

the rim joist acting as the chord in place and removed in Figures 3.11 and 3.12 respectively.


Figure 3.11 Test Configuration with Rim-Joists (and corner opening)

Figure 3.12 Test Configuration without Rim-Joists


Blocking is the term used for the short framing members that span between joists and

serve to interlock the unsupported joints between sheathing panels. They can have the same

cross-sectional dimensions as the joists (full-depth blocking improves noise and vibration

dampening), or blocks can simply be smaller lumber laid flat. In this investigation, specimen

configurations with blocking used 2 x 4’s laid flat installed between joists where each line of

unsupported sheathing panels joints would fall prior to installing the sheathing. The blocks were

fastened to the joists on each side with two 16d common toe nails. Plywood panel edges that fell

over the blocks are nailed every 6 inches with 10d duplex nails for easy removal to simulate the

blocked and unblocked conditions. To reconfigure the specimen without blocking, the sheathing

nails were extracted, the diaphragm was tilted on-end with forklifts, and the blocks were

removed. Likewise, replacing blocking involved tilting the diaphragm up to install new 2x 4

blocks from below.

A potentially significant unknown in diaphragm design is the effect of walls on the

horizontal stiffness. Walls of a structure transfer wind loads to the floors to which they are

connected. Also the mass of the walls themselves present added lateral loads to diaphragms

during earthquakes. These walls however, especially the flexural stiffness of their own sill plate,

may also benefit a floor diaphragm by helping to resist these same lateral loads.

For testing purposes, four-foot high walls were installed along the two chord edges of

specimens. These walls were constructed of 2 x 4 studs at 16 in. o.c. and 7/16 in. OSB sheathing

on the outside. The 2 x 4 sill plate at the bottom of the walls was fastened through the plywood

sheathing to the floor joists below with 3½ x ¼ in. self-tapping Simpson® screws for a strong

connection yet easy removal. For the 16 x 20 ft. specimens, regardless of orientation, the walls


were set in place and removed with a long, cable-supported, boom attached to a large forklift.

For the 40 ft. long specimens, the walls on each side were built in 20 ft. sections, set in place

with the boom, and connected in the center. From then on, the davits at each end of the walls

accompanied by braces in the center allow repeated installation and removal of walls. Braces

were used to stabilize the wall segments for the 10 x 40 ft diaphragm specimens.

Figure 3.13 Test Configuration with Walls


(a) Walls Lowered and Attached (b) Walls Unfastened and Raised

Figure 3.14 Wall-Lifting Davits

Figure 3.15 10 x 40 ft. Specimen with Walls and Wall-Braces


Current trends in construction involve the use of adhesives for an ever-widening range of

applications. In this case the method of fastening sheathing panels to framing members was

varied between nailed only and nailed plus sprayed adhesive. The material used was sprayed,

two-part, self-expanding, poly-isocyanurate foam adhesive manufactured by ITW Foamseal. The

foam adhesive was tested using coupon tests to quantify its stiffness as a connection. The

connection stiffness was determined to be equivalent to that obtained by using elastomeric

adhesives typically used in wood floor construction. After having tested all of the nailed-only

configurations, is the foam adhesive was applied to the underside of fully constructed specimens

that could be safely tilted on-end (i.e. the two 16 x 20 and the two 20 x 16 ft. specimens).

Adhesives were not used on the 10 x 40 ft specimens due to the specimens flexibility, which

made lifting the specimens without damage impossible. A photograph of the foam adhesive

being applied is shown in Figure 3.16.


Figure 3.16 Application of Sprayed Foam Adhesive

Figure 3.17 Foam Adhesive Shown After Removal of a Sheathing Panel


Sheathing nail density was varied for a few tests on the third and fourth specimens, both

of which were 20 x 16 ft. loaded perpendicular to the joists. The nail pattern was changed from

6-12 to 3-12 on the fully sheathed and nailed only configurations. In other words, nail spacing

around the perimeter of each sheathing panel (where supported by joists or blocking) was

increased from 6 in. to 3 in. o.c. using easily removable 10d duplex nails. The 3-12 nail pattern

was tested while the walls and blocking parameters remain variable.

3.5 Instrumentation

As with any physical experiment, application of a stress to a laboratory specimen is

meaningless without the ability to measure the results. Movements, deflections, and loads were

measured at multiple locations on the diaphragm specimens using electronic sensors of various

types in conjunction with a computer controlled Data AcQuisition system (DAQ). The DAQ

used for this project was LABTECH, a Windows PC-based program. Prior to testing, all

instruments used in this research project were carefully calibrated for accurate results. Before

any series of tests in a day, all instruments were checked to make sure they were correctly

mounted, functioning properly, and zeroed. Due to the exposed conditions of the outside testing

facility, all instruments were demounted and taken inside or covered with plastic to protect from

inclement weather, dew, and frost.

An internal Linear Variable Displacement Transducer (LVDT) measured the deflections

caused by the hydraulic actuator. Signals from this highly sensitive device were transmitted to

the computer controller, which in turn used the information to control the actuator. Loads


measured by the 50 kip Interface load cell were recorded by the DAQ and had no effect on the

displacement-controlled actuator.

The custom-built load cells at each end of the diaphragm measured the reaction loads,

both in tension and compression due to the cyclic loads from the actuator. These reactions

simulated the shear loads that supporting walls of an actual structure must withstand. Prior to

use, these load cells, as described in Section 3.2, were separately calibrated in tension only

(compression was not feasible due to a pinned-pinned condition when using special calibration

fixtures) on a universal testing machine with an excitation of 10 Volts. Both were loaded

incrementally to 40 kips in tension, and in each case the perfectly linear calibration plot proved

that no yielding within the load cell occurred. The slopes of these lines were used in the DAQ as

multipliers to convert the output voltage signals from the load cells into equivalent values of

load.

Horizontal movement of the plywood sheathing relative to the framing members below

was measured at two locations with external LVDT’s. An aluminum bracket mounted to the

end-joist at each rear corner to hold the barrels of a pair of LVDT’s in place horizontally. The

plungers of these instruments beared upon metal tabs, which were screwed and glued to the

plywood at the rear corners of the diaphragm. The LVDT’s of each pair pointed in orthogonal

directions to account for biaxial sheathing movement.

String Potentiometers were used at multiple locations to determine diaphragm movement,

deformation, and slippage from the test frame. Seven string-pots were set along the front face of

the specimens to measure the global deflection. A string-pot waas attached to each steel side

support frame to determine the slip in the side load cell connections and between the diaphragm


itself and the steel frame. Likewise, a string-pot was mounted to the steel load channel in the

center to determine any slip its lag screw connection to the specimen. Two string-pots were

mounted diagonally on each side of the diaphragm centerline to record the deformation caused by

shear deflection during testing. Schematics illustrating the positions of each displacement

transducer for each specimen configuration are presented in Figures 3.18 through 3.20.

GR1Concrete Back Wall

LVDTL-NS

LVDTL-EW

GL1SlipL

DL1

SlipC

DL2 DR1

GL2 GL3 GC

LVDTR-NS

LVDTR-EW

DR2

3" x 5" Steel Tube

GR2 SlipRGR3

Figure 3.18 Instrumentation Plan for 16’ x 20’ Specimen


Concrete Back WallGC GR1 GR2 GR3 SlipRGL1 GL2 GL3SlipL

SlipC

DL1 DL2 DR1 DR2

LVDTL-NS

LVDTL-EW

LVDTR-EW

LVDTR-NS

Figure 3.19 Instrumentation Plan for 20’ x 16’ Specimen


Con

cret

e B

ack

Wal

lG

CG

R1

GR

2G

R3

Slip

RG

L1G

L2G

L3S

lipL

Slip

C

DL1

DL2

DR

1D

R2

LVD

TL-

NS

LVD

TL-

EW

LVD

TR

-EW

LVD

TR

-NS

Figu

re 3

.20

Ins

trum

enta

tion

Plan

for 1

0’ x

40’

Spe

cim

en


Figure 3.21 LVDT’s and Mounting Bracket

3.6 Test Protocol

In most cases of experimental research, how a specimen is stressed and to what extent, is

equally as important as the specimen’s characteristics. In this project great care was taken not to

apply deflections so large that specimens reached or exceeded their yield point and were

damaged. On the other hand, it is critical to apply sufficient deflection to obtain valid test data.

This limit was found for each size and orientation of specimen by loading monotonically in small

increasing increments until signs of diaphragm damage are seen or heard or until the slope of the

load/deflection curve, shown in real-time on the DAQ computer screen, appeared to be

decreasing. The deflection amount used for all tests was slightly lower than the largest


monotonic deflection. Additionally, deflections for this project followed a pattern that somewhat

simulates the cyclic loading of earthquakes, only not nearly as rapid, since this apparatus is not

intended or equipped to be shake-table testing.

The load protocol for all tests, except those to failure, was five dynamic sinusoidal cycles

at the predetermined deflection, ±0.25” for specimens one and two (20 ft. wide), ±0.20” for

specimens three and four (16 ft. wide), and ±0.80” for specimens five and six (40 ft. wide). The

frequency of these cycles is set in the actuator controller at 0.0833 Hz for test durations of 60

seconds. Five cycles, or even possibly less, are adequate since this project does not incorporate

the effects of load fatigue.

While not a primary focus of this project, the last test of each specimen was an attempt to

cause failure. The CUREE protocol (Krawinkler, 2000) used for these tests was a deflection-

controlled quasi-static cyclic load history. This protocol is based on a finite series of cycles with

plateaus and peaks of increasing amplitude. Yield deflection, ∆, was estimated for each

specimen and used as the reference deflection from which amplitudes of other cycles may be

determined. If failure did not occur by the end of the series, the CUREE protocol allows for

additional cycles at higher amplitudes until the specimen fails.

3.7 Stiffness Analysis

The diaphragm deflection measurements were used to determine the effective global,

shear, and bending stiffness. The analysis used in this investigation follows that outlined by

Fischer et al. (2001). The following sections outline the steps of the analysis used to quantify the

shear and bending stiffness values.


3.7.1 Global Stiffness

The general deflected shape that includes contributions of both shear and bending

deformation is shown in Figure 3.22. The global deformations that are illustrated in Figure 3.22

were used to quantify the global stiffness values for the diaphragm. The hysteresis recorded

during one of the tests is shown in 3.23, along with an illustration of the variable cyclic stiffness,

kglobal. The cyclic stiffness is the secant stiffness defined by the peak load and associated

displacements (maximum and minimum) for the test. The effective global stiffness was

calculated using the equation

maxmin

maxmin

∆+∆+

=FF

kglobal (3.1)

where Fmin and Fmax represent the minimum and maximum resistance recorded during the cyclic

test, and ∆min and ∆max represent the minimum and maximum global displacements recorded

during the test.

F2

d

F2

shearwall

F

L

global

total

Figure 3.22 Global Deflections of Diaphragm (Fischer et al., 2001)


Figure 3.23 Global Load-Deflection Hysteretic Curves Illustrating the Cyclic Stiffness

Variable, kglobal.

3.7.2 Shear Stiffness

The shear deformation was determined using the changes in the length of the diagonals

measured by the potentiometers located on each side of the diaphragm. The assumed shear

deformation pattern is illustrated in Figure 3.24. The shear deflection of the diaphragm, ∆shear,

can be expressed as

2L

shear γ=∆ (3.2)

where γ is the shear strain that can be determined using the diagonal deflection measurements.


s

b b

L2

L2

γ

F 2

F 2

F2

F2

d

∆

Figure 3.24 Assumed Shear Deformation Pattern for Diaphragms (Fischer et al., 2001)

bddb 22

21

2)( +•∆+∆=γ (3.3)

where ∆1 and ∆2 are the diagonal measurements of a pair of instruments, b is the width of the

diaphragm measured by an instrument pair, and d is the depth of the diaphragm measured by an

instrument pair as shown in Figure 3.24


Similar to the method used to determine the global stiffness in Equation 3.1, the shear

stiffness was determined using Equation 3.3.

max,min,

max,min,

shearshear

shearshearshear

FFk

∆+∆

+= (3.3)

where ∆shear,min and ∆shear,min are the minimum and maximum shear deformations determined

using Equations 3.3 and 3.2. Fshear,min and Fshear,max are the shear force applied during the test, and

is equal to one-half of the total force applied to the diaphragm during the test. The theoretical

shear deformation for a simply supported beam with a point load applied at the centerline is

shearshear GA

LF2=∆ (3.4)

where GAshear is the shear stiffness of the diaphragm. Rearranging equation 3.4, GAshear can be

expressed in terms of kshear as

2LkGA shearshear = (3.5)

3.7.3 Bending Stiffness

The bending stiffness was determined by first determining the bending deflection by

subtracting the shear deflection from the global deflection.

shearglobalbending ∆−∆=∆ (3.6)

The bending stiffness, kbending, was determined using Equation 3.7, which is similar to Equation

3.3 used to determine the shear stiffness.


max,min,

maxmin

bendingbendingbending

FFk

∆+∆+

= (3.7)

where Fmin and Fmax are the minimum and maximum loads measured during the cyclic tests

respectively, and ∆bending,min and ∆bending,max are the associated minimum and maximum bending

deflections determined using Equation 3.6. Using elastic bending theory, the theoretical bending

deflection of a simply supported beam with a concentrated load at the center is

EIFL

bending 48

3

=∆ (3.8)

where EI is the flexural stiffness of the diaphragm. Equation 3.8 can be rearranged to solve for

the bending stiffness, EI, in terms of kbending as

48

3LkEI bending= (3.9)

Results and Discussion | 51

Chapter 4 – Results and Discussion

4.1 Introduction

Objectives of the current research were to perform necessary testing and analyses in order

to justify effects of various parameters on diaphragm cyclic stiffness to provide improved

methods for predicting diaphragm deflections. In this chapter are described results of moisture

content and wood density analyses, nail bending tests, and tests conducted on six wood-framed

and plywood-sheathed diaphragms subject to sets of 5 fully-reversing cycles of displacement to

determine the elastic cyclic stiffness of the diaphragm and the CUREE displacement protocol at

the end to try and determine the ultimate strength of the diaphragm, as described in Chapter 2.

Parameters investigated for all diaphragms included nail schedule, openings within diaphragms,

locations of openings within diaphragms, presence of chord members, presence of walls above

diaphragms, installation of blocking, and installation of adhesive between sheathing and framing.

Additionally, effects of aspect ratio and loading direction were investigated for different pairs of

similarly tested diaphragms, as previously described. Test results include discussions and

tabulated comparisons of the effects of different diaphragm configurations on global cyclic

stiffness for all specimens and variations observed for the different aspect ratios and loading

directions. Global stiffness results are further separated into flexural stiffness and shear stiffness

components. Conclusions are drawn regarding the effects of the various diaphragm permutations

and the implications of those effects for predicting diaphragm deflections. Strength information

was obtained for three of the six specimens.


4.2 Specimen Test Orientations

A total of six diaphragms were cyclically tested in sets of two, utilizing three different

aspect ratios and two different loading directions. Specimens 1 and 2 were 16 ft by 20 ft, with 16

ft joists, and loads applied parallel to the joists. Specimens 3 and 4 were 20 ft by 16 ft, also with

16 ft joists, and loads applied perpendicular to the joists. Specimens 5 and 6 were 10 ft by 40 ft,

using 10 ft joists, and loads applied parallel to the joists.

4.3 Moisture Content and Density Analyses

Samples were procured from joists and plywood used to fabricate Specimen 1, and solely

from the joists from Specimens 2, 3, 4, 5, and 6. These samples were analyzed to determine

moisture content and density. Observed measurements included initial mass in grams, dried

mass in grams and amount of water displaced in grams. From these observations, the moisture

content and dried density of each joist (and sheathing for Specimen 1) was determined and

averages were calculated for each of the six specimens. These results are presented in Table 4.1.

Additionally, moisture meter readings were recorded at the beginning of various days during

testing for Specimens 1, 2, 3, and 4. No moisture meter readings were recorded for Specimens 5

and 6. Moisture meter readings were obtained for joists and average readings across joists are

presented in Table 4.2. Individual test results are provided in Appendix G.


Table 4.1 - Average Moisture Content and Density from Sample Analysis

Specimen 1

Specimen 2

Specimen3

Specimen 4

Specimen 5

Specimen 6

Joists Plywood Joists Joists Joists Joists Joists Average Moisture Content

(%)

22

10

22

29

23

21

15

Average Density (g/cc)

0.47

0.58

0.48

0.48

0.51

0.48

0.48

As can be seen from the moisture content values in Table 4.1, the moisture content was

reasonably consistent for the joists, with the exception of Specimen 6. The values for each

specimen in Table 4.2 show that the moisture content remained fairly consistent during the

testing of each specimen as well. Therefore, no effort to adjust the diaphragm values was made.


Table 4.2 - Average Moisture Content from Moisture Meter Readings

Specimen 1 Specimen 2 Specimen 3 Specimen 4

Day 1 14 % 19 % 19 % 23 % Day 2 13 % 18 % 19 % 22 % Day 3 14 % 17 % 19 % 22 % Day 4 13 % 17 % 18 % 22 % Day 5 14 % 18 % 18 % 23 %

4.4 Nail Bending Test Results

Tests were also conducted to assess the bending yield moment of nails utilized to

fabricate the diaphragms. Tests were performed according to ASTM F1575: Test Methods for

Determining Bending Yield Moments of Nails (ASTM, 1996) on 10d duplex nails, 10d nails for

use with a pneumatic gun, 16d duplex nails, and 16d nails for use with a pneumatic gun. Two

sets of tests were conducted for 10d duplex and 16d duplex nails to represent the two different

lots that those nails came from. Each set of tests contained between five and seven specimens

and the average bending yield moments, utilizing 5% offset rationale, are presented in Table 4.3.

Table 4.3 - Average Bending Yield Moments for Nails

Nail Type

Diameter

5% Offset Strength

Average Bending Yield

Moment

10d Duplex Set 1 0.148 in. (3.76 mm)

166 lbs (739 N)

115 psi (0.795 kN/mm2)

10d Duplex Set 2 0.148 in. (3.76 mm)

172 lbs (767 N)

120 psi (0.825 kN/mm2)

10d Gun Nails 0.128 in. (3.25 mm)

110 lbs (493 N)

119 psi (0.819 kN/mm2)

16d Duplex Set 1 0.162 in. (4.12 mm)

124 lbs (552 N)

98.5 psi (0.679 kN/mm2)

16d Duplex Set 2 0.162 in. (4.12 mm)

132 lbs (586 N)

105 psi (0.720 kN/mm2)

16d Gun Nails 0.162 in. (4.12 mm)

123 lbs (548 N)

109 psi (0.749 kN/mm2)


4.5 Parameter Effects on Diaphragm Stiffness

4.5.1 Introduction

Each of six diaphragms was testing for effects on cyclic stiffness due to a variety of

construction permutations. For each of the permutations, diaphragms were cyclically loaded to

displacements prior to any significant degradation in stiffness. An effort was made to use the

maximum displacement possible without causing the envelope curve to lose stiffness and to not

cause the load resisted to decay between successive cycles. In the following sections,

quantitative comparisons are made for various parameter effects, utilizing cyclic stiffness for the

diaphragms. Comparisons are made to the values determined for the diaphragms that were

nailed, fully sheathed, had no walls or chords and were unblocked as the baseline for each

diaphragm. Specimens 5 and 6 were only tested in a blocked configuration; therefore the

baseline stiffness for theses two specimens are for the blocking installed configurations.

Baseline stiffness for each of the diaphragms is provided in Table 4.4 utilizing a peak-to-peak

analysis for stiffness determination.

Table 4.4 - Baseline Cyclic Stiffness for Fully Sheathed, Nailed, Unblocked* Diaphragms with no Walls or Chords

Specimen Global

Stiffness (kips-inch)

Flexural Stiffness

(kips-inch2)

Left Side Shear Stiffness

(kips)

Right Side Shear Stiffness

(kips) 1 29.4 2.61x107 2610 2210 2 27.5 2.51x107 2640 2060 3 46.3 3.21x107 3290 2470 4 26.6 1.37x107 1430 1410 5 4.00 1.22x107 2080 1940 6 3.40 1.25x107 900 1090

*Specimens 5 and 6 were only tested in blocked configurations


In order to compare direction of loading and aspect ratio effects, cyclic stiffness averages for

each pair of diaphragms were calculated and are presented in Table 4.5.

Table 4.5 - Average Baseline Cyclic Stiffness for Fully Sheathed, Nailed, Unblocked* Diaphragms with no Walls or Chords for Matched Pairs of

Diaphragms

Specimens

Global Stiffness

(kips-inch)

Flexural Stiffness

(kips-inch2)

Left Side Shear Stiffness

(kips)

Right Side Shear Stiffness

(kips) 1 and 2 28.5 2.56x107 2630 2140 3 and 4 36.5 2.29x107 2360 1940 5 and 6 3.70 1.24x107 1490 1520

*Specimens 5 and 6 were only tested in blocked configurations

While Specimens 3 and 4 averaged the highest global stiffness, Specimens 1 and 2 averaged

greater flexural and shear stiffness than any of the other diaphragms. Specimens 5 and 6

averaged the lowest global, flexural, and shear stiffness of the diaphragms tested, which makes

sense because these diaphragms had the highest aspect ratio. However, if one were to view

Specimen 4 as an anomaly, Specimen 3 has the highest flexural stiffness, which makes sense

because this configuration always has the end joist acting as a chord. Based on these findings,

using the average values for each configuration, it was concluded that diaphragms with aspect

ratios of 4:1 were far less stiff than diaphragms with aspect ratios of 4:5 or 5:4, regardless of joist

orientation. Diaphragms loaded perpendicular to the joists that were deeper than those loaded

parallel to the joists were globally stiffer, but flexural and shear stiffness was greatest for

diaphragms loaded parallel to the joists.


4.5.2 Effects of Blocking

In order to assess the effects of installing blocking in a floor diaphragm, Specimens 2, 3

and 4 were subject to loading under various configurations of blocked and unblocked treatments.

All test configurations for Specimen 1 were unblocked and all test configurations for Specimens

5 and 6 were blocked, therefore effects of blocking could not be determined for those specimens.

Stiffness values and comparisons of testing configuration differences for Specimens 3 and 4 were

averaged to obtain general trends in stiffness for that loading orientation. Specimen 2 was tested

with and without chords; therefore the effects of chords are included within the analysis of

blocking effects. In general, when blocking was installed, increases in global stiffness and shear

stiffness were observed. Effects of blocking on flexural stiffness values were varied, resulting in

increased or decreased flexural stiffness values for different test configurations. Table 4.6

provides comparisons of blocking effects for test configurations where chord and adhesive

effects are included. Further test configurations and results are discussed below.

Table 4.6 provides global, shear and flexural stiffness values and comparisons for test

configurations in blocked and unblocked conditions where effects of chords and use of adhesives

are also considered. Increases in global stiffness and shear stiffness were observed in all

configurations with the installation of blocking. Diaphragms that were nailed only, displayed the

most dramatic increases in global stiffness (86.0% - 101.8%) and shear stiffness (134.2% -

174.6%). Diaphragms constructed with adhesive and nails displayed lower, yet still significant

increases in global stiffness (38.9% - 43.6%) and shear stiffness (42.9% - 105.1%). The average

increase in global stiffness for Specimens 3 and 4 constructed with nails and adhesive was only

2.5% and was not considered to be a practical difference. Specimen 2 showed a greater increase

in global and shear stiffness from the blocked to unblocked condition in the case where there


were no chords and the diaphragm was only nailed than when chords were included. Conversely,

the configuration where the diaphragm was constructed utilizing adhesive and nails there was a

smaller increase in global and shear stiffness when chords were included. Flexural stiffness

increased in some instances and decreased in others when blocking was installed. Decreases in

flexural stiffness were observed when chords were installed and only nails were used for

Specimen 2 and for Specimens 3 and 4 when the diaphragms were constructed using nails and

adhesive. The other configurations shown in Table 4.6 displayed moderate increases in flexural

stiffness (21.8% - 52.2%) when blocking was added, except where chords and adhesive were

used on Specimen 2, and blocking only increased the flexural stiffness an insignificant 4%.

These results make sense because blocking reduces the deformation of the sheathing

panels and therefore should have the largest effect on the shear stiffness because the sheathing

resists the shear forces. The effect of blocking should increase both the bending and shear

stiffness when there is no designated chord member because in this case, the sheathing must

resist both bending and shear action with the sheathing. Blocking should also cause a decrease in

the relative resistance of bending stiffness when the chord is present because the total force is

being resisted more by shear action when the shear stiffness is increased.


Table 4.6 - Cyclic Stiffness Comparisons for Blocked and Unblocked Configurations

Specimen 2 Blocked, with Chords, no

Walls, Nailed only, Fully Sheathed

Unblocked, with Chords, no Walls, Nailed only, Fully

Sheathed

Change from unblocked to blocked

Global

(kip/in.) Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

66.2 6183 5.28E+07 35.6 2640 6.61E+07 86.0% 134.2% -20.1% Blocked, no Chords, no


Unblocked, no Chords, no Walls, Nailed only, Fully

Sheathed


Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

55.5 5626.5 3.82E+07 27.5 2347 2.51E+07 101.8% 139.7% 52.2%

Blocked, with Chords, no Walls, Nails and Adhesive, Fully

Sheathed

Unblocked, with Chords, no Walls, Nails and Adhesive,

Fully Sheathed


Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

67.5 6185.5 5.47E+07 47 3829 5.26E+07 43.6% 61.5% 4.0% Blocked, no Chords, no

Walls, Nails and Adhesive, Fully Sheathed

Unblocked, no Chords, no Walls, Nails and Adhesive,

Fully Sheathed


Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

46.4 4691.5 3.13E+07 33.4 3284 2.57E+07 38.9% 42.9% 21.8% Averaged Values for Specimen 3 and Specimen 4

Blocked, no Walls, Nailed only, Fully Sheathed

Unblocked, no Walls, Nailed only, Fully Sheathed


Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

63.7 5015 2.62E+07 36.5 2150 2.29E+07 87.3% 174.6% 22.8%

Blocked, no Walls, Nails and Adhesive, Fully Sheathed

Unblocked, no Walls, Nails and Adhesive, Fully Sheathed


Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

81.2 9500 2.19E+07 79.2 4631 4.43E+07 2.5% 105.1% -50.7%


A full table of effects blocking had on the diaphragms is presented in Appendix A. The

presence or absence of walls did not have a distinct result on blocking effects. Diaphragms with

center openings displayed greater increases in global and shear stiffness when blocking was

added, while diaphragms with corner openings did not display a distinct trend in global, shear or

flexural stiffness with added blocking. As previously mentioned, in all cases blocking resulted in

an increase in global and shear stiffness, but not necessarily flexural stiffness.

4.5.3 Effects of Adhesives

The effects of constructing the test diaphragms with a combination of nails and adhesive

on cyclic stiffness were assessed through various test configurations. Relevant comparisons

between diaphragm configurations utilizing just nails and those utilizing a combination of nails

and adhesive are provided in this section to determine the effects of including adhesives. The

adhesive used and the method of application was discussed in Chapter III. Test configurations

using adhesive were performed for Specimens 1, 2, 3 and 4. Specimens 5 and 6 were only tested

utilizing nailed construction and are not included in the following comparisons. All test

configurations for Specimen 1 were performed in the unblocked condition. Table 4.7 provides

several comparisons between configurations with and without adhesive and includes effects of

chords and blocking. Further test configurations and results are discussed below.


configurations using solely nails and a combination of nails and adhesive, where effects of

chords and blocking are also considered. Increases in global stiffness and shear stiffness were

observed in all configurations presented in Table 4.7 for configurations that included adhesive

except for Specimen 2 in the blocked condition. For Specimen 2 the shear stiffness did not


change when adhesive was used, but the global stiffness did increase. Diaphragms constructed

with chords displayed only slightly more increases in global and shear stiffness than diaphragms

constructed without chords when adhesive was included. Unblocked diaphragms showed

dramatic increases in global stiffness (32.0% - 88.7%) and shear stiffness (45% - 125.6%) when

adhesive was used, while blocked diaphragms showed lower increases in global stiffness (2.0% -

28.0%) and shear stiffness (0.0% - 84.0%) when adhesive was used. This makes sense because

the blocking has already restricted the sheathing and increased the shear stiffness significantly.

The adhesive augments the blocking effects. Increases in global and shear stiffness were much

greater for Specimens 3 and 4 than for Specimens 1 and 2 for the blocked and unblocked

conditions, suggesting a potential effect of loading direction when adhesives are utilized.

Flexural stiffness changes varied from –16.0% to 35.8% with the inclusion of adhesive within the

structural system. It is clear from Table 4.7 that adhesive application served to increase global

and shear stiffness in most configurations, and that these effects were more pronounced for

unblocked diaphragms than for blocked diaphragms.

Table 4.7 - Cyclic Stiffness Comparisons for Floor Diaphragms with and without Adhesive

Averaged Values for Specimen 1 and Specimen 2 Unblocked, with Chords, no Walls, Nails and Adhesive,

Fully Sheathed


Sheathed Change with Adhesive

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

49.1 3997 5.56E+07 40.1 2866 6.62E+07 23.5% 39.9% -16.0% Unblocked, no Chords, no Walls, Nails and Adhesive,

Fully Sheathed


Sheathed

Change with Adhesive

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

34.4 3259 2.69E+07 28.5 2379 2.56E+07 20.9% 37.1% 5.0%


Specimen 2 Blocked, with Chords, no

Walls, Nails and Adhesive, Fully Sheathed

Blocked, with Chords, no Walls, Nailed only, Fully


Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

67.5 6186 5.47E+07 66.2 6183 5.28E+07 2.0% 0.0% 3.6% Unblocked, with Chords, no Walls, Nails and Adhesive,

Fully Sheathed



Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

47.0 3829 5.26E+07 35.6 2640 6.61E+07 32.0% 45.0% -20.4% Averaged Values for Specimen 3 and Specimen 4

Blocked, no Walls, Nails and Adhesive, Fully

Sheathed


Change with Adhesive

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

81.2 9495 2.19E+07 63.7 5015 2.62E+07 28.0% 84.0% -11.6% Unblocked, no Walls, Nails

and Adhesive, Fully Sheathed Unblocked, no Walls, Nailed

only, Fully Sheathed Change with Adhesive

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

67.1 4375 3.13E+07 36.5 2149 2.29E+07 88.7% 125.6% 35.8%

A full table of adhesive application effects on the diaphragms is presented in Appendix B.

In most, but not all, cases, diaphragms constructed with adhesive and nails had greater global and

shear stiffness than similar diaphragms constructed with only nails. Changes in flexural stiffness

of diaphragms were not consistent when adhesive was included in the construction. The

presence or absence of walls did not have a well-defined result on adhesive application effects in

terms of cyclic stiffness. Most diaphragms with center openings displayed greater increases in

global, shear and flexural stiffness when adhesive was included, while diaphragms with corner

openings did not display a distinct trend in global, shear or flexural stiffness with inclusion of

adhesive.


4.5.4 Effects of Center Openings

Several diaphragm configurations were tested with an opening in the center of the

diaphragm in order to assess effects of openings in the center of a floor or roof system, such as

would be present for stairs, great rooms, or skylights. Comparisons between diaphragm

configurations with openings in the center and those with full sheathing are provided in this

section to determine potential reductions in cyclic stiffness caused by the openings. Exact

locations of openings and methods of construction were discussed in Chapter III. Test

configurations with center openings were performed for Specimens 1, 2, 3 and 4. Specimens 5

and 6 were only tested with full sheathing or corner openings and are not included in the

following comparisons. All test configurations for Specimen 1 were performed in the unblocked

condition. Table 4.8 provides several comparisons between configurations with full sheathing

and center openings. Further test configurations and results are discussed below.


configurations with and without center openings, including effects of blocking, chords and the

use of adhesive. Decreases in global stiffness and shear stiffness were observed in all

configurations provided in Table 4.8, and all but one configuration displayed decreases in

flexural stiffness when a center opening was present in the diaphragms. A slightly greater

decrease in global and shear stiffness was observed in diaphragms without chords than those with

chords. Flexural stiffness increased when a center opening was created in diaphragms with

chords, suggesting that a significant portion of stiffness had been shifted from shear resistance to

bending resistance. Decreases in global stiffness were equivalent for practical purposes (less

than 5% difference) for diaphragms constructed with adhesive than for those without. Shear


stiffness decreases were slightly more for diaphragms constructed with adhesive and flexural

stiffness decreases were greater for diaphragms constructed without adhesive. Blocked

diaphragms displayed greater losses in global and shear stiffness when center openings were

present, whereas unblocked diaphragms displayed greater decreases in flexural stiffness when

center openings were present. This again reinforces the concept that blocking diaphragms

reduces the demand for bending resistance by restricting the sheathing movement and increasing

the shear resistance. Given that decreases in global stiffness (-24.4% to -47.3%) and shear

stiffness (-35.4% to –60.1%) were observed in all configurations presented in Table 4.8, it

follows that openings in floor and roof systems reduce diaphragm stiffness. Effects of center

openings on stiffness were minimally affected by blocking, adhesives and diaphragm chords.

If one now considers that removal of the sheathing to produce the center opening entailed

removal of approximately 50% of the sheathing along the center lines (in either direction) of the

specimen, but did not change the chord conditions, one would expect the shear stiffness of the

diaphragm to decrease in proportion to the length of sheathing removed. This deduction assumes

the traditional deep beam analysis assumptions of all bending is resisted by the chords and all

shear is resisted by the sheathing. It also assumes the traditional uniform distribution of shear

force across the width of the diaphragm. With these assumptions, the shear stiffness should be

reduced approximately 50%, which is what was observed. One would also expect that the

bending stiffness for the diaphragms without designated chord members to be reduced according

to the change in moment of inertia. However, depending on the orientation of the joists, their

stiffening effects change, but for Specimens 1 and 2 the moment of inertia should be close to that

of the sheathing only. However, the trend for when adhesives were used is correct and the nailed


only condition is not. The trends in Specimens 3 and 4 are correct, but not exact, because the

joists are running perpendicular to the loading and act like a distributed chord.

Table 4.8 - Cyclic Stiffness Comparisons for Floor Diaphragms with and without Center Openings


Center Opening

Unblocked, with Chords, no Walls, Nails and Adhesive,

Fully Sheathed Change with Center Opening

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

37.4 2591 7.21E+07 49.1 3997 5.56E+07 -24.2% -35.4% 28.6% Unblocked, no Chords, no Walls, Nails and Adhesive,

Center Opening



Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

22.0 1707 2.31E+07 34.4 3259 2.96E+07 -36.1% -47.6% -13.7% Unblocked, no Chords, no Walls, Nails and Adhesive,

Center Opening



Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

22.0 1707 2.31E+07 34.4 3259 2.96E+07 -36.1% -47.6% -13.7% Unblocked, no Chords, no Walls, Nailed only, Center

Opening


Sheathed Change with Center Opening

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

18.8 14.18 1.94E+07 28.5 2379 2.56E+07 -33.9% -40.3% -24.1% Averaged Values for Specimen 3 and Specimen 4

Blocked, no Walls, Nailed only, Center Opening


Change with Center Opening

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

33.6 1970 2.45E+07 63.7 5015 2.62E+07 -47.3% -60.1% -11.3% Unblocked, no Walls,

Nailed only, Center Opening Unblocked, no Walls,

Nailed only, Fully Sheathed Change with Center Opening

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

22.3 1027 1.86E+07 36.5 2149 2.29E+07 -35.4% -45.4% -19.0%


A full table of effects of center openings on the diaphragms is presented in Appendix C.

In all tested configurations, diaphragms fabricated with center openings maintained lower global

and shear stiffness values than similar diaphragms constructed with full sheathing. Changes in

flexural stiffness of diaphragms varied when center openings were included in the construction.

Decreases in global, shear and flexural stiffness were slightly greater for diaphragms without

walls than those with walls. Decreases in stiffness resulting from center openings as affected by

blocking were similar for all specimens to those reported in Table 4.8, with blocked diaphragms

displaying greater losses in global, shear and flexural stiffness with center openings than

unblocked diaphragms.

4.5.5 Effects of Corner Openings

Several diaphragm configurations were tested with an opening in the corner of the

diaphragm in order to assess effects of openings in a floor system, such as would be present for

stairs. Comparisons between diaphragm configurations with openings in the corner and those

with full sheathing are provided in this section to determine potential reductions in cyclic

stiffness caused by the openings. Exact locations of corner openings and methods of

construction were discussed in Chapter III. Test configurations with corner openings were

performed for all specimens. All test configurations for Specimen 1 were performed in the

unblocked condition and all test configurations for Specimens 5 and 6 were conducted in the

blocked condition. Table 4.9 provides several comparisons between configurations with full

sheathing and corner openings. Further test configurations and results are discussed below.


configurations with and without corner openings, including effects of blocking, chords and use of


adhesive. Corner openings affected different sides of diaphragms, therefore the shear stiffness

values presented in Table 4.9 are broken down into L. Shear (shear for the left side of the

diaphragm) and R. Shear (shear for the right side of the diaphragm). Specimens 3, 4, 5, and 6

had corner openings on the left side while Specimens 1 and 2 had corner openings on the right

side of the diaphragms. In all configurations tested, decreases in shear stiffness occurred on the

side of the specimen with the corner opening. Much lower decreases in shear stiffness were

observed on sides without corner openings and several configurations experienced increases in

shear stiffness on the side without openings. This was particularly evident on Specimens 5 and

6, whose aspect ratios were much less than the other four specimens. This increase in shear

stiffness is attributed to the redistribution of shear forces occurring within the diaphragms in the

presence of corner openings. Decreases in global stiffness (-9.2% to –28.0%) and flexural

stiffness (-2.7% to –18.4%) were observed in all configurations provided in Table 4.9 when a

corner opening was present in the diaphragms. A greater decrease in global and shear stiffness

on the side with the opening was observed in diaphragms with chords than those without chords.

A small decrease (-3.8%) in shear stiffness occurred on the side without the opening when chords

were present and an increase (18.5%) in shear stiffness occurred on the side without the opening

when chords were not present, suggesting that more of the shear resistance was redistributed in

diaphragms without chords. Differences in flexural stiffness decreases were negligible for

practical purposes when a corner opening was created in diaphragms with or without chords.

Diaphragms constructed with adhesive and nails displayed greater decreases in global and

flexural stiffness than diaphragms constructed with only nails. Insignificant differences in shear

stiffness on sides with openings were observed between diaphragms with or without adhesive. A

minimal decrease (-1.6%) in shear stiffness occurred on the side without the opening when


adhesive was used and an increase (18.5%) in shear stiffness occurred on the side without the

opening when adhesive was not used, suggesting that more of the shear resistance was

redistributed in diaphragms constructed with adhesive. Blocked diaphragms displayed greater

losses in global and shear stiffness on the side with the opening, whereas unblocked diaphragms

displayed negligible decreases in flexural stiffness when corner openings were present. Sides

without openings displayed a moderate decrease (-10.3%) in shear stiffness in blocked

diaphragms and an insignificant increase (0.2%) in unblocked diaphragms. Specimens 5 and 6

exhibited decreases in global stiffness, flexural stiffness and shear stiffness on the side with the

opening. A dramatic increase (39.8%) in shear stiffness occurred in Specimens 5 and 6 on the

side without the corner opening, suggesting that the lower aspect ratio contributed to a greater

redistribution of shear resistance within these diaphragms.

Table 4.9 - Cyclic Stiffness Comparisons for Floor Diaphragms with and without Corner Openings

Averaged Values for Specimen 1 and Specimen 2 Unblocked, with Chords, no Walls,

Nailed only, Corner Opening Unblocked, with Chords, no Walls,

Nailed only, Fully Sheathed Change with Corner Opening

Global

(kip/in.) L. Shear

(kip) R. Shear

(kip) Flexural (kip-in.2)

Global (kip/in.)

L. Shear(kip)

R. Shear(kip)

Flexural (kip-in.2)

Global(kip/in.)

L. Shear (kip)

R. Shear (kip)

Flexural(kip-in.2)

28.7 2926 1324 6.44E+07 40.1 3043 2689 6.62E+07 -28.0% -3.8% -49.8% -2.7% Unblocked, no Chords, no Walls,

Nailed only, Corner Opening Unblocked, no Chords, no Walls,


Global

(kip/in.) L. Shear

(kip) R. Shear


Global (kip/in.)

L. Shear(kip)

R. Shear(kip)

Flexural (kip-in.2)

Global(kip/in.)

L. Shear (kip)

R. Shear (kip)

Flexural(kip-in.2)

25.9 3105 1486 2.46E+07 28.5 2622 2135 2.56E+07 -9.2% 18.5% -30.6% -4.2% Unblocked, no Chords, no Walls,

Nails and Adhesive, Corner Opening Unblocked, no Chords, no Walls,

Nails and Adhesive, Fully Sheathed Change with Corner Opening

Global

(kip/in.) L. Shear

(kip) R. Shear


Global (kip/in.)

L. Shear(kip)

R. Shear(kip)

Flexural (kip-in.2)

Global(kip/in.)

L. Shear (kip)

R. Shear (kip)

Flexural(kip-in.2)

28.5 3700 1839 2.36E+07 34.4 3767 2751 2.69E+07 -17.4% -1.6% -33.3% -12.5% Unblocked, no Chords, no Walls,

Nailed only, Corner Opening Unblocked, no Chords, no Walls,


Global

(kip/in.) L. Shear

(kip) R. Shear


Global (kip/in.)

L. Shear(kip)

R. Shear(kip)

Flexural (kip-in.2)

Global(kip/in.)

L. Shear (kip)

R. Shear (kip)

Flexural(kip-in.2)

25.9 3105 1486 2.46E+07 28.5 2622 2135 2.56E+07 -9.2% 18.5% -30.6% -4.2%


Averaged Values for Specimen 3 and Specimen 4

Blocked, no Walls, Nailed only, Corner Opening


Change with Corner Opening

Global (kip/in.)

L. Shear (kip)

R. Shear(kip)

Flexural (kip-in.2)

Global (kip/in.)

L. Shear(kip)

R. Shear(kip)

Flexural (kip-in.2)

Global(kip/in.)

L. Shear (kip)

R. Shear (kip)

Flexural(kip-in.2)

49.2 2151 4579 2.13E+07 63.7 4927 5104 2.62E+07 -22.7% -56.5% -10.3% -17.9%

Unblocked, no Walls, Nailed only, Corner Opening



Global (kip/in.)

L. Shear (kip)

R. Shear(kip)

Flexural (kip-in.2)

Global (kip/in.)

L. Shear(kip)

R. Shear(kip)

Flexural (kip-in.2)

Global(kip/in.)

L. Shear (kip)

R. Shear (kip)

Flexural(kip-in.2)

32.2 1319 1956 1.86E+07 36.5 2359 1940 2.29E+07 -12.7% -40.9% 0.2% -18.4% Averaged Values for Specimen 5 and Specimen 6

Blocked, no Walls, with Chords, Nailed only, Corner Opening

Blocked, no Walls, with Chords Nailed only, Fully Sheathed


Global (kip/in.)

L. Shear (kip)

R. Shear(kip)

Flexural (kip-in.2)

Global (kip/in.)

L. Shear(kip)

R. Shear(kip)

Flexural (kip-in.2)

Global(kip/in.)

L. Shear (kip)

R. Shear (kip)

Flexural(kip-in.2)

6.3 582 2202 7.05E+07 7.6 1018 1475 7.42E+07 -18.5% -44.9% 39.8% -6.1%

If the concept of uniform shear distribution used to consider estimating changes in shear

stiffness is applied to this type of opening in a similar way center openings were considered, the

estimate of stiffness reduction is not very good for corner openings. A single sheet of sheathing

(4 ft x 8 ft) was removed in all cases for the corner opening. This resulted in a 25% reduction in

sheathing for the 16 ft x 20 ft configurations (Specimens 1 and 2), a 20% reduction for the 20 ft x

16 ft configurations (Specimens 3 and 4) and a 40% reduction for the 10 ft x 40 ft configurations

(Specimens 5 and 6). However, the associated average reductions in shear stiffness were 30.6% -

49.8% for Specimens 1 and 2, 40.9% - 56.9% for Specimens 3 and 4, and 44.9% for Specimens 5

and 6. In other words, the effects of corner openings are much more severe than the general

design theory would predict. The scant data also seems to indicate that as the size of the corner

opening gets larger with respect to the width, the assumption of uniform shear distribution

becomes more valid. However, the results indicate that the shear is not distributed uniformly

near the ends of the diaphragm.


A full table of effects of corner openings on the diaphragms is presented in Appendix D.

In all tested configurations, diaphragms fabricated with corner openings exhibited lower global

and shear stiffness on the side with the openings than similar diaphragms constructed with full

sheathing. Changes in flexural stiffness and shear stiffness on the side without openings of

diaphragms varied when corner openings were included in the construction. Distinct trends in

global, shear and flexural stiffness differences were not evident between diaphragms without

walls than those with walls when corner openings were included. Decreases in stiffness resulting

from corner openings as affected by blocking were similar for all specimens to those reported in

Table 4.8, with blocked diaphragms displaying greater losses in global and shear stiffness with

corner openings than unblocked diaphragms. Differences in flexural stiffness between blocked

and unblocked diaphragms were inconclusive.

4.5.6 Effects of Chords

In practice, different situations result in diaphragms being constructed with designated

chords in some instances and without designated chords in others. Several configurations were

tested with and without chords in order to assess the effects of including designated chords with

regard to cyclic stiffness. Comparisons between diaphragm configurations with chords and

without chords are provided in this section to determine potential increases in cyclic stiffness

resulting from chords. Orientations of chords and methods of construction were discussed in

Chapter III. Test configurations with and without chords were performed for Specimens 1, 2, 5

and 6. All test configurations for Specimen 1 were performed in the unblocked condition and all

test configurations for Specimens 5 and 6 were conducted in the blocked condition. Table 4.10


provides several comparisons between configurations with and without chords. Further test

configurations and results are discussed below.


configurations with and without chords, including effects of blocking, walls and use of adhesive.

In all configurations presented in Table 4.10, increases in global stiffness (19.3% - 101.3%) were

observed with the addition of chords. Lower increases in shear stiffness (2.5% - 22.7%) were

observed when chords were included, and in one instance a decrease in shear stiffness was noted.

Flexural stiffness for all tested configurations increased with the inclusion of chords, and many

configurations experienced gains in flexural stiffness of greater than 100%. Specimens 5 and 6

exhibited particularly large increases in flexural stiffness when chords were included, while shear

stiffness values increased minimally or decreased. The relatively large effect of chords on

Specimens 5 and 6 is to be expected, because the narrower diaphragm results in a higher bending

action and a reduced shear action. This is not the same trend found in the traditional beam

theory.

A greater increase in global and flexural stiffness was observed in diaphragms without

walls than those with walls, when chords were added. This trend is attributed to the bottom plate

of the wall and some of the wall sheathing acting as the chord when the rim joist was not present.


Table 4.10 - Cyclic Stiffness Comparisons for Floor Diaphragms with and without Chords


Fully Sheathed


Fully Sheathed Change after Including Chords

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural(kip-in.2)

49.1 3997 5.56E+07 34.4 3259 2.69E+07 42.7% 22.7% 106.6%Unblocked, with Chords, no



Sheathed Change after Including Chords

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural(kip-in.2)

40.1 2866 6.62E+07 28.5 2379 2.56E+07 40.4% 20.4% 158.7%

Specimen 2 Blocked, with Chords, no Walls, Nailed only, Fully

Sheathed

Blocked, no Chords, no Walls, Nailed only, Fully Sheathed

Change after Including Chords

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural(kip-in.2)

66.2 6183 5.28E+07 55.5 5627 3.82E+07 19.3% 9.9% 38.2% Unblocked, with Chords, no



Sheathed Change after Including Chords

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural(kip-in.2)

35.6 2640 6.61E+07 27.5 2347 2.51E+07 29.5% 12.5% 163.3%Averaged Values for Specimen 5 and Specimen 6

Blocked, with Chords, no Walls,

Nailed only, Fully Sheathed


Change after Including Chords

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural(kip-in.2)

7.6 1246 7.42E+07 3.7 1503 1.24E+07 101.3% -18.6% 500.3%Blocked, with Chords, with


Blocked, no Chords, with Walls,

Nailed only, Fully Sheathed Change after Including Chords

Global


Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural(kip-in.2)

9.0 1427 1.03E+08 7.0 1370 4.18E+07 28.2% 2.5% 152.2%


Diaphragms constructed with adhesive and nails displayed negligibly greater increases in

global and shear stiffness than diaphragms constructed with only nails. A greater increase in

flexural stiffness was observed in diaphragms constructed only with nails than those constructed

with nails and adhesive. Unblocked diaphragms displayed greater gains in global, shear and

flexural stiffness than blocked diaphragms when chords were included due to the significantly

higher shear stiffness associated with blocked diaphragms.

A full table of effects of including designated chords in the construction of diaphragms is

presented in Appendix E. In general, the addition of chords resulted in increases in global, shear

and flexural stiffness of the diaphragms. Flexural stiffness was more dramatically affected by

inclusion of chords than global or shear stiffness. Increases in stiffness as affected by walls were

similar for all specimens to those reported in Table 4.10, with diaphragms without walls

displaying greater gains in global, shear and flexural stiffness with chords than diaphragms with

walls. Diaphragms with center openings experienced greater increases in global, shear and

flexural stiffness when chords were added than fully sheathed specimens. Diaphragms with

corner openings exhibited lower increases in global and shear stiffness when chords were

included than fully sheathed specimens. Differences in flexural stiffness between diaphragms

with corner openings and fully sheathed diaphragms did not display a distinct trend with respect

to the effects of chords.

4.5.7 Effects of Walls

Floor diaphragms are typically constructed with walls on top of them while roof

diaphragms are frequently constructed without any type of wall. Several configurations were

therefore tested with and without walls in order to assess the effects of including walls with


regard to cyclic stiffness. Comparisons between diaphragm configurations with walls and

without walls are provided in this section to determine potential increases in cyclic stiffness

resulting from the addition of walls. Specifications of walls and methods of construction were

discussed in Chapter III. Test configurations with and without walls were performed for all six

specimens. All test configurations for Specimen 1 were performed in the unblocked condition

and all test configurations for Specimens 5 and 6 were conducted in the blocked condition.

Table 4.11 provides several comparisons between configurations with and without walls. Further

test configurations and results are discussed below.


configurations with and without walls, including effects of blocking, chords and use of adhesive.

In all configurations presented in Table 4.11, increases in global stiffness (2.5% - 34.1%) were

observed with the addition of walls. Slightly lower increases in shear stiffness (1.1% - 21.0%)

were observed when walls were included in the construction of the diaphragms. Most

configurations in Table 4.11 exhibited an increase in flexural stiffness (9.9% - 106.3%) with the

inclusion of walls; with one set of averages displaying a negligible decrease (-2.2%) in flexural

stiffness. A greater increase in global, shear and flexural stiffness was observed in diaphragms

without chords than those with chords, when walls were added. Diaphragms constructed with

adhesive and nails displayed lower increases in global, shear and flexural stiffness than

diaphragms constructed with only nails, and a decrease in flexural stiffness for one specimen was

observed when walls were included in the diaphragms constructed with nails and adhesive.

Unblocked diaphragms displayed negligibly greater gains in global stiffness than blocked

diaphragms when walls were included. Greater increases in flexural stiffness were observed in


unblocked diaphragms with the addition of walls, while increases in shear stiffness were slightly

greater for blocked diaphragms.

A full table of effects of including walls in the construction of diaphragms is presented in

Appendix F. In general, the addition of walls resulted in increases in global, shear and flexural

stiffness of the diaphragms. As with the addition of chords, flexural stiffness was more

dramatically affected by inclusion of walls than global or shear stiffness. Differences in global,

shear and flexural stiffness between diaphragms with center or corner openings and fully

sheathed diaphragms did not display a distinct trend with respect to the effects of walls. All of

these trends are in line with what traditional diaphragm theory would predict since the walls

essentially are acting to enlarge the chords (or flanges) of the deep beam. The wall connection

also restricts the movement of the sheathing as well, and therefore all three stiffness values are

affected.


Table 4.11 - Cyclic Stiffness Comparisons for Floor Diaphragms with and without Walls

Averaged Values for Specimen 1 and Specimen 2 Unblocked, with Chords, with



Sheathed Change after Including Walls

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

42.3 2907 7.47E+07 40.1 2866 6.62E+07 5.3% 1.1% 12.7% Unblocked, no Chords, with Walls,

Nailed only, Fully Sheathed Unblocked, no Chords, no Walls,

Nailed only, Fully Sheathed Change after Including Walls

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

38.3 2779 5.29E+07 28.5 2379 2.56E+07 34.1% 16.7% 106.3%

Specimen 2

Blocked, no Chords, with Walls, Nailed only, Fully Sheathed


Change after Including Walls

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

65.3 6002 5.29E+07 55.5 5627 3.82E+07 17.7% 6.7% 38.5% Unblocked, no Chords, with Walls,

Nailed only, Fully Sheathed Unblocked, no Chords, no Walls,

Nailed only, Fully Sheathed Change after Including Walls

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

32.9 2413 4.75E+07 27.5 2347 2.51E+07 19.6% 2.8% 89.2% Averaged Values for Specimen 3 and Specimen 4

Unblocked, with Walls, Nailed only, Fully Sheathed



Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

42.4 2596 2.56E+07 36.5 2149 2.29E+07 15.8% 21.0% 9.9% Unblocked, with Walls,

Nails and Adhesive, Fully Sheathed

Unblocked, no Walls, Nails and Adhesive, Fully

Sheathed Change after Including Walls

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

66.8 4660 2.77E+07 67.1 4375 3.13E+07 2.5% 7.4% -2.2% Averaged Values for Specimen 5 and Specimen 6

Blocked, with Chords, with Walls, Nailed only, Fully Sheathed

Blocked, with Chords, no Walls, Nailed only, Fully Sheathed


Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

Global (kip/in.)

Shear (kip)

Flexural (kip-in.2)

9.0 1427 1.03E+08 7.6 1246 7.42E+07 17.5% 13.0% 39.3%


4.6 Diaphragm Strength Results

Several of the six specimens that were tested for stiffness effects were taken to failure

following the final stiffness test utilizing the CUREE protocol (Krawinkler et at., 2001).

Specimen 1 experienced buckling of the steel test fixture and was therefore not able to be failed.

Specimen 2 was taken to failure in the configuration with chords, no walls, blocked, fully

sheathed, and constructed with nails and adhesive. Failure load for Specimen 2 was 53,200 lbs

(53.2 kip), with a resulting maximum shear load of 1,662 lbs/ft (1.66 kip/ft). Failure occurred in

Specimen 2 due to nail failure along the left edge of the diaphragm, where nail heads pulled

through, nails bent severely, nail heads broke off, nails pulled out of joist, and in some cases

enlarged the nail hole until the fasteners became ineffective. Rim boards were pulled away from

and some splitting was observed where the rim boards were connected to the end joists.

Specimen 3 could not be failed due to lifting of the specimen off of the test bed at the

unrestrained ends furthest from the side of load application. Specimen 4 exceeded the upper

limit of the load cell attached to the hydraulic actuator (55,000 lbs or 1,375 lb/ft shear load)

without displaying any signs of failure and was therefore not considered to be taken to failure.

Failure occurred in Specimen 5 at a load of 17,900 lbs (17.9 kip), providing a maximum

shear load of 895 lbs/ft (0.90 kip/ft) for a test configuration with chords, no walls, blocked, fully

sheathed and constructed with nails only. Specimen 5 failed as a result of complete separation of

the left side end joist from the sheathing due to nail withdrawal and nail fatigue failure in

addition to separation of the rim joist from the sheathing along the left front corner due to nails

tearing through the sheathing.

Specimen 6 was taken to failure in the configuration with chords, no walls, unblocked,

fully sheathed and constructed with nails only, and achieved a failure load of 13,400 lbs (13.4

kip), providing a maximum shear load of 670 lbs/ft (0.67 kip/ft). This is considerably less than

the failure achieved by Specimen 5, which makes sense because Specimen 6 was an unblocked

diaphragm. Failure in Specimen 6 occurred as a result of complete separation of the right side

end joist from the sheathing due to nail withdrawal and nail-head pull-through. Rim-joist

separation from sheathing was also observed along the right side due to nail tear-out from the

sheathing, and slight nail tear-out from the sheathing along 4 ft of the left end joist.


4.7 Conclusions

Results from the regime of cyclic tests conducted on six diaphragms were discussed in

this chapter. Comparisons among the various were presented in order to determine which

parameters affected global, shear and flexural stiffness of the diaphragms and how the parameters

affected one another. Chapter V includes generalized conclusions of how blocking, adhesive,

chords, openings and walls affect the global, shear and flexural stiffness of diaphragms subject to

cyclic lateral loading and what implications these affects have on the design of diaphragms for

seismic load resistance.

Summary and Conclusions | 79

Chapter 5 – Summary and Conclusions

5.1 Summary

Task 1.4.2 of the CUREE-Caltech Woodframe Project consisted of testing six

diaphragms to determine their stiffness characteristics were affected by various construction

details. The diaphragms were constructed to include three aspect ratios (4:5; 5:4, and 4:1). The

4:5 and 5:4 aspect ratio diaphragms were tested under two loading conditions, one with the load

applied parallel to the joists and perpendicular to the continuous joints in the sheathing, and one

with the load applied perpendicular to the joists and parallel to the continuous joints in the

sheathing. In addition, the effects of the following construction details on the diaphragm

stiffness was investigated:

• Corner openings

• Center openings

• Presence of blocking

• Use of adhesives to attach the sheathing

• Presence of designated chord members

• Presence of walls with a continuous bottom plate attached to the floor above the

designated chord members.

In all cases, the specimens were tested using a fully reversing cyclic displacement pattern

that consisted of 5 cycles at a displacement that was on the verge of causing measurable damage

to the specimen. This displacement was arrived at by repeating the cyclic test on the fully

sheathed configuration until the locus of peak displacement and load began to show signs of a

change in stiffness of the specimen. This displacement was then used for all of the remaining

configurations a given specimen was tested with. Upon completion of the stiffness tests, each

specimen was subjected to the CUREE displacement protocol in an attempt to fail the specimen.

Comparative results on stiffness and strength are presented in Chapter IV.


5.2 Conclusions Several key results of the stiffness tests are presented in this section. However, the

number of different configuration tested is so large, that additional results can be obtained is

additional analysis of the results of these tests are combined with the results of other tasks of the

CUREE-Caltech Woodframe Project. Therefore, all of the tests results are presented in the

appendices. The key results of the Task 1.4.2 tests are:

• Loading diaphragms parallel to the joists provides the highest shear stiffness, but

the highest global and bending stiffness values are achieved when the diaphragm

is loaded perpendicular to the joists.

• Blocking is the most effective method of stiffening a diaphragm with the global

stiffness increasing 86%-102% and shear stiffness increasing 134%-175% when

the sheathing was attached with nails only. The changes in stiffness for when

adhesives were used to attach the sheathing were 39%-44% and 43% - 105% for

global and shear stiffness respectively.

• The use of adhesives has the most dramatic effect on diaphragms that are not

blocked. The increase in global stiffness is 32%-89% and the increase in shear

stiffness is 45%-126%. Blocked diaphragms showed a smaller increase in

stiffness, 2%-28% and 0%-84% for global and shear stiffness respectively.

• The reduction in stiffness associated with the size of openings that are located in

the center of the diaphragm, the reduction in stiffness is proportional to the

percentage of sheathing removed, when considering the width of the diaphragm.

Summary and Conclusions | 81

• The reduction in stiffness associated with corner openings is not proportional to

the percentage of sheathing removed. The reduction in stiffness is greater than the

percentage of sheathing removed.

• As would be expected, the presence of a designated chord member significantly

increases both the global stiffness and bending stiffness. However, the bending

stiffness without chords is significant and is dependent on the orientation of the

joists with respect to the loading.

• Walls that are effectively attached to the diaphragm framing can significantly

increase the effectiveness of the chord and increase the bending stiffness of the

diaphragm.


References | 83

References Anderson, G.A. and Bundy, D.S. (1990). Stiffness Of Screw-Fastened, Metal-Clad, Timber-Framed Roof Diaphragms With Openings In The Sheathing, Transactions in Agriculture, ASAE 33(1), 266-273. Corda, D.N. (1982). The In-Plane Shear Response of Timber Diaphragms, Masters’s Thesis, West Virginia University, Morgantown, WV. Countryman, D. (1952). Lateral Tests On Plywood Sheathed Diaphragms, Laboratory Report No. 55, Douglas Fir Plywood Association, Tacoma, Washington. Countryman, D. and Colbenson, P. (1955). 1954 Horizontal Plywood Diaphragm Tests, Laboratory Report No. 63, Douglas Fir Plywood Association, Tacoma, Washington. GangaRao, H.V.S. and Luttrell, L.D. (1980). “Preliminary Investigations Into The Response of Timber Diaphragms,” Proceedings of a Workshop on Design Of Horizontal Wood Diaphragms, Applied Technology Council, Berkely, California, November 19-20, 1979, 277-295. Hankins, S.C., Easterling, W.S., and Murray, T.M. (1992). Vulcraft 1.5BI Cantilever Diaphragm Tests, Virginia Polytechnic Institute and State University, Report No. CE/VPI-ST-92/01, Blacksburg, VA. Hausmann, C.T. and Esmay, M.L. (1977). The Diaphragm Strength of Pole Buildings, Transactions of the ASAE, 20(1), 114-116. Jewell, R.B. (1981). The Static and Dynamic Experimental Analysis Of Wooden Diaphragms., Masters’s Thesis, West Virginia University, Morgantown, WV. Polensek, A. (1979). “Damping Capacity of a Nailed Wood-Joist Floor,” Wood Science, 11(3), 155-159. Roberts, J.D. (1983). Finite Element Analysis Of Horizontal Timber Diaphragms, Masters’s Thesis, West Virginia University, Morgantown, WV. Stillinger, J.R. and Countryman, D. (1953). Lateral Tests on Full-Scale Plywood Sheathed Roof Diaphragms, Laboratory Report No. T-5, Oregon Forest Products Laboratory, Corvallis, Oregon. Tissell, J.R. and Elliott, J.R. (1997). Plywood Diaphragms, Laboratory Report No. 138, American Plywood Association, Tacoma, Washington. Tissell, J.R. (1966). 1966 Horizontal Plywood Diaphragm Tests. Laboratory Report No. 106, American Plywood Association, Tacoma, Washington.


Widjaja, B.R. (1993). Analytical Investigation of Composite Diaphragms Strength and Behavior, Master’s Thesis, Virginia Polytechnic Institute and State University, Blacksburg, VA. Woeste, F. and Townsend, M. (1991). Simple-Beam Diaphragm Test Considerations, ASAE Paper No. 91-4059, ASAE, St. Joseph, MI. Wright, B.W. and Manbeck, H.B. (1993). Finite Element Analysis of Wood-Framed, Metal-Clad Diaphragm Panels, Transactions of the ASAE, 36(3), 895-904.

Appendix A: Effects of Blocking on Diaphragm Cyclic Stiffness | 85

Appendix A - Effects of Blocking on Diaphragm Cyclic Stiffness

A.1 Introduction

In order to assess the effects of installing blocking in a floor diaphragm, Specimens 2, 3

and 4 were subject to loading under various configurations of blocked and unblocked treatments.

All test configurations for Specimen 1 were unblocked and all test configurations for Specimens

5 and 6 were blocked, therefore effects of blocking could not be determined for those specimens.

Included in this appendix are the tabulated comparisons between blocked and unblocked

configurations.

A.2 Comparisons of Blocking Effects

Presented below are tables of comparisons for effects of blocking for Specimens 2, 3 and

4, and the averaged comparisons for Specimens 3 and 4.

Table A.1 - Cyclic Stiffness Comparisons for Blocked and Unblocked Configurations for Specimen 2*

B, C, NW, N, FS UB, C, NW, N, FS Change from unblocked to blocked

Global Shear Flexural Global Shear Flexural Global Shear Flexural 66.2 6183 5.28E+07 35.6 2640 6.61E+07 86.0% 134.2% -20.1%

B, NC, NW, N, FS UB, NC, NW, N, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 55.5 5627 3.82E+07 27.5 2347 2.51E+07 101.8% 139.7% 52.2%

B, NC, W, N, FS UB, NC, W, N, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 65.3 6002 5.29E+07 32.9 2413 4.75E+07 98.5% 148.7% 11.4%

B, C, W, N, FS UB, C, W, N, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 71.8 6387 6.21E+07 36.4 2555 6.61E+07 97.3% 150.0% -6.1%

B, C, NW, NA, FS UB, C, NW, NA, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 67.5 6186 5.47E+07 47 3829 5.26E+07 43.6% 61.5% 4.0%


Table A.1 - (Cont’d) Cyclic Stiffness Comparisons for Blocked and Unblocked Configurations for Specimen 2*

B, NC, NW, NA, FS UB, NC, NW, NA, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 46.4 4692 3.13E+07 33.4 3284 2.57E+07 38.9% 42.9% 21.8%

B, NC, W, NA, FS UB, NC, W, NA, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 54.9 5099 4.36E+07 41 3338 4.94E+07 33.9% 52.8% -11.7%

B, C, W, NA, FS UB, C, W, NA, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 67.9 6086 5.97E+07 47.3 3501 7.49E+07 43.6% 73.8% -20.3%

B, C, NW, N, CTO UB, C, NW, N, CTO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 34.5 2419 5.55E+07 24.9 1609 8.22E+07 38.6% 50.3% -32.5% B, NC, NW, N, CTO UB, NC, NW, N, CTO Change from unblocked to blocked

Global Shear Flexural Global Shear Flexural Global Shear Flexural 24.3 2039 2.23E+07 19.4 1570 2.03E+07 25.3% 29.8% 9.9%

B, NC, W, N, CTO UB, NC, W, N, CTO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 31.2 2174 4.66E+07 23.5 1603 4.95E+07 32.8% 35.6% -5.9%

B, C, W, N, CTO UB, C, W, N, CTO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 36.9 2489 6.30E+07 28.2 1831 7.94E+07 30.9% 35.9% -20.7% B, C, NW, NA, CTO UB, C, NW, NA, CTO Change from unblocked to blocked

Global Shear Flexural Global Shear Flexural Global Shear Flexural 38.7 2990 4.96E+07 32.1 2288 5.70E+07 20.6% 30.7% -13.0% B, NC, NW, NA, CTO UB, NC, NW, NA, CTO Change from unblocked to blocked

Global Shear Flexural Global Shear Flexural Global Shear Flexural 25.9 2244 2.32E+07 22.9 1793 2.48E+07 13.1% 25.2% -6.5% B, NC, W, NA, CTO UB, NC, W, NA, CTO Change from unblocked to blocked


B, C, W, NA, CTO UB, C, W, NA, CTO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 41.3 3082 6.36E+07 36.7 2549 7.61E+07 12.5% 20.9% -16.4%

B, C, NW, N, CRO UB, C, NW, N, CRO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 44.5 3944 5.17E+07 26.7 1984 6.02E+07 66.7% 98.8% -14.1%



B, NC, NW, N, CRO UB, NC, NW, N, CRO Change from unblocked to blocked


B, NC, W, N, CRO UB, NC, W, N, CRO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 44.1 3724 5.56E+07 25 1931 4.98E+07 76.4% 92.9% 11.6%

B, C, W, N, CRO UB, C, W, N, CRO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 46.7 3921 5.72E+07 27.9 2011 6.85E+07 67.4% 95.0% -16.5% B, C, NW, NA, CRO UB, C, NW, NA, CRO Change from unblocked to blocked

Global Shear Flexural Global Shear Flexural Global Shear Flexural 47.9 4219 5.72E+07 31.7 2694 5.31E+07 51.1% 56.6% 7.7% B, NC, NW, NA, CRO UB, NC, NW, NA, CRO Change from unblocked to blocked

Global Shear Flexural Global Shear Flexural Global Shear Flexural 37.4 3599 3.00E+07 26.4 2744 2.20E+07 41.7% 31.2% 36.4% B, NC, W, NA, CRO UB, NC, W, NA, CRO Change from unblocked to blocked


B, C, W, NA, CRO UB, C, W, NA, CRO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural

51 4428 6.60E+07 33.3 2667 6.73E+07 53.2% 66.0% -1.9%

*B = Blocked, UB = Unblocked, C = with Chords, NC = no Chords, W = with Walls, NW = no Walls, N = Nailed only, NA = Nails and Adhesive, FS = Fully Sheathed, CRO = Corner Opening, CTO = Center Opening, Global Stiffness measured in kip/inch, Shear Stiffness measured in kip, and Flexural Stiffness measured in kip-inch2.



B, NW, N, FS UB, NW, N, FS Change from unblocked to blocked

Global Shear Flexural Global Shear Flexural Global Shear Flexural 65 4417 3.27E+07 46.3 2880 3.21E+07 40.4% 53.4% 1.9%

B, W, N, FS UB, W, N, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural

68 4507 3.66E+07 54.3 3453 3.68E+07 25.2% 30.5% -0.5% B, NW, NA, FS UB, NW, NA, FS Change from unblocked to blocked

Global Shear Flexural Global Shear Flexural Global Shear Flexural 69 6134 2.23E+07 79.2 4631 4.43E+07 -12.9% 32.5% -49.7%

B, W, NA, FS UB, W, NA, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 71.6 6296 2.35E+07 68.6 4272 3.34E+07 4.4% 47.4% -29.6%

B, NW, N, CTO UB, NW, N, CTO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 35.3 2006 3.53E+07 24.1 996 2.62E+07 46.5% 101.4% 34.7%

B, W, N, CTO UB, W, N, CTO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 36.9 2489 6.30E+07 28.2 1831 7.94E+07 30.9% 35.9% -20.7%

B, NW, N, CRO UB, NW, N, CRO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 49.7 2965 2.85E+07 42 2106 2.59E+07 18.3% 40.8% 10.0%

B, W, N, CRO UB, W, N, CRO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 53.8 3059 3.70E+07 47.3 2394 3.09E+07 13.7% 27.8% 19.7%

B, NW, N3, FS UB, NW, N3, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 83.9 6425 3.32E+07 49.2 3047 3.49E+07 70.5% 110.9% -4.9%

B, W, N3, FS UB, W, N3, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 86.2 6313 3.69E+07 58.6 3803 3.51E+07 47.1% 66.0% 5.1%

*B = Blocked, UB = Unblocked, C = with Chords, NC = no Chords, W = with Walls, NW = no Walls, N = Nailed only, NA = Nails and Adhesive, N3 = Nailed only using a 3:12 nailing schedule, FS = Fully Sheathed, CRO = Corner Opening, CTO = Center Opening, Global Stiffness measured in kip/inch, Shear Stiffness measured in kip, and Flexural Stiffness measured in kip-inch2.





B, W, N, FS UB, W, N, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural

64 5828 2.00E+07 30.4 1732 1.44E+07 110.5% 236.6% 38.9% B, NW, NA, FS UB, NW, NA, FS Change from unblocked to blocked


B, W, NA, FS UB, W, NA, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 91.7 11821 2.16E+07 65 5049 2.20E+07 41.1% 134.1% -1.8%

B, NW, N, CTO UB, NW, N, CTO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 31.8 1934 1.37E+07 20.5 1058 1.10E+07 55.1% 82.8% 24.5%

B, W, N, CTO UB, W, N, CTO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 34.6 2160 1.39E+07 24.1 1276 1.23E+07 43.6% 69.3% 13.0%

B, NW, N, CRO UB, NW, N, CRO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 48.7 3765 1.68E+07 22.3 1169 1.13E+07 118.4% 222.2% 48.7%

B, W, N, CRO UB, W, N, CRO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 51.7 4246 1.67E+07 25.3 1405 1.23E+07 104.3% 202.2% 35.8%

B, NW, N3, FS UB, NW, N3, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 77.3 7178 2.14E+07 38.2 2394 1.63E+07 102.4% 199.8% 31.3%

B, W, N3, FS UB, W, N3, FS Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 80.1 7969 2.09E+07 42.1 2766 1.70E+07 90.3% 188.2% 22.9%

B, NW, NA, CRO UB, NW, NA, CRO Change from unblocked to blocked Global Shear Flexural Global Shear Flexural Global Shear Flexural 67.4 7185 1.75E+07 43.2 3020 1.64E+07 56.0% 137.9% 6.7%



B, W, NA, CRO UB, W, NA, CRO Change from unblocked to blocked




Table A.4 - Averaged Cyclic Stiffness Comparisons for Blocked and Unblocked Configurations for Specimens 3 and 4*



B, W, N, FS UB, W, N, FS Change from unblocked to blockedGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

66 5167 2.83E+07 42.4 2592 2.56E+07 67.9% 133.5% 19.2% B, NW, NA, FS UB, NW, NA, FS Change from unblocked to blocked


B, W, NA, FS UB, W, NA, FS Change from unblocked to blockedGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 81.65 9058 2.26E+07 66.8 4660 2.77E+07 22.7% 90.8% -15.7%

B, NW, N, CTO UB, NW, N, CTO Change from unblocked to blockedGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 33.55 1970 2.45E+07 22.3 1027 1.86E+07 50.8% 92.1% 29.6%

B, W, N, CTO UB, W, N, CTO Change from unblocked to blockedGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 35.75 2324 3.85E+07 26.2 1554 4.59E+07 37.2% 52.6% -3.8%

B, NW, N, CRO UB, NW, N, CRO Change from unblocked to blockedGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 49.2 3365 2.27E+07 32.2 1637 1.86E+07 68.4% 131.5% 29.4%

B, W, N, CRO UB, W, N, CRO Change from unblocked to blockedGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 52.75 3652 2.69E+07 36.3 1900 2.16E+07 59.0% 115.0% 27.8%

B, NW, N3, FS UB, NW, N3, FS Change from unblocked to blockedGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 80.6 6801 2.73E+07 43.7 2720 2.56E+07 86.4% 155.4% 13.2%

B, W, N3, FS UB, W, N3, FS Change from unblocked to blockedGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 83.15 7141 2.89E+07 50.4 3284 2.61E+07 68.7% 127.1% 14.0%



Appendix B: Effects of Adhesive on Diaphragm Cyclic Stiffness | 93

Appendix B - Effects of Adhesive on Diaphragm Cyclic Stiffness

B.1 Introduction

The effects of constructing test diaphragms with a combination of nails and adhesive on

cyclic stiffness were assessed through various test configurations. Comprehensive comparisons

between diaphragm configurations utilizing just nails and those utilizing a combination of nails

and adhesive are provided in this appendix. Test configurations using adhesive were performed

for Specimens 1, 2, 3 and 4. Specimens 5 and 6 were only tested utilizing nailed construction

and are not included in the following Tables.

B.2 Comparisons of Adhesive Effects

Presented below are tables of comparisons for effects of adhesive for Specimens 1, 2, 3

and 4, and averaged comparisons for Specimens 1 and 2, and for Specimens 3 and 4.

Table B.1 - Cyclic Stiffness Comparisons for Specimen 1 with and without Adhesive*

NC, NW, NA, CRO NC, NW, N, CRO Change Including AdhesiveGlobal Shear Flexural Global Shear Flexural Global Shear Flexural30.5 2795 2.51E+07 29.2 2506 2.69E+07 4.5% 11.6% -6.7%

C, NW, NA, CRO C, NW, N, CRO Change Including AdhesiveGlobal Shear Flexural Global Shear Flexural Global Shear Flexural37.7 2889 5.82E+07 30.7 2265 6.86E+07 22.8% 27.5% -15.2%

C, W, NA, CRO C, W, N, CRO Change Including AdhesiveGlobal Shear Flexural Global Shear Flexural Global Shear Flexural39.5 3019 7.27E+07 33 2378 7.60E+07 19.7% 26.9% -4.3%

NC, W, NA, CRO NC, W, N, CRO Change Including AdhesiveGlobal Shear Flexural Global Shear Flexural Global Shear Flexural35.5 2876 6.21E+05 37.5 2603 8.31E+07 -5.3% 10.5% -99.3%

NC, W, NA, FS NC, W, N, FS Change Including AdhesiveGlobal Shear Flexural Global Shear Flexural Global Shear Flexural43.3 3645 4.34E+07 43.7 3145 5.83E+07 -0.9% 15.9% -25.6%


Table B.1 - (Cont’d) Cyclic Stiffness Comparisons for Specimen 1 with and without Adhesive*

C, W, NA, FS C, W, N, FS Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural51.3 4055 6.32E+07 48.2 3259 8.32E+07 6.4% 24.4% -24.0%

C, NW, NA, FS C, NW, N, FS Change Including AdhesiveGlobal Shear Flexural Global Shear Flexural Global Shear Flexural51.2 4166 5.86E+07 44.5 3091 6.63E+07 15.1% 34.8% -11.6%

NC, NW, NA, FS NC, NW, N, FS Change Including AdhesiveGlobal Shear Flexural Global Shear Flexural Global Shear Flexural35.4 3234 2.81E+07 29.4 2410 2.61E+07 20.4% 34.2% 7.7% NC, NW, NA, CTO NC, NW, N, CTO Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural21 1622 2.14E+07 18.1 1266 1.85E+07 16.0% 28.1% 15.7% C, NW, NA, CTO C, NW, N, CTO Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural42.6 2894 8.72E+07 29.1 1845 5.83E+07 46.4% 56.9% 49.6%

C, W, NA, CTO C, W, N, CTO Change Including AdhesiveGlobal Shear Flexural Global Shear Flexural Global Shear Flexural41.3 2913 7.31E+07 30.2 1904 6.19E+07 36.8% 53.0% 18.1%

NC, W, NA, CTO NC, W, N, CTO Change Including AdhesiveGlobal Shear Flexural Global Shear Flexural Global Shear Flexural29.9 2193 4.06E+07 22.9 1438 4.15E+07 30.6% 52.6% -2.2%



B, C, NW, NA, FS B, C, NW, N, FS Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 67.5 6186 5.47E+07 66.2 6183 5.28E+07 2.0% 0.0% 3.6% B, NC, NW, NA, FS B, NC, NW, N, FS Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 46.4 4692 3.13E+07 55.5 5627 3.82E+07 -16.4% -16.6% -18.1%



B, NC, W, NA, FS B, NC, W, N, FS Change Including Adhesive


B, C, W, NA, FS B, C, W, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 67.9 6086 5.97E+07 71.8 6387 6.21E+07 -5.4% -4.7% -3.9% B, C, NW, NA, CTO B, C, NW, N, CTO Change Including Adhesive


B, NC, NW, NA, CTO B, NC, NW, N, CTO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 25.9 2244 2.32E+07 24.3 2039 2.23E+07 6.6% 10.1% 4.0% B, NC, W, NA, CTO B, NC, W, N, CTO Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 33.9 2600 4.56E+07 31.2 2174 4.66E+07 8.7% 19.6% -2.1% B, C, W, NA, CTO B, C, W, N, CTO Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 41.3 3082 6.36E+07 36.9 2489 6.30E+07 11.9% 23.8% 1.0% B, C, NW, NA, CRO B, C, NW, N, CRO Change Including Adhesive


B, NC, NW, NA, CRO B, NC, NW, N, CRO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 37.4 3599 3.00E+07 38.6 3926 2.93E+07 -3.1% -8.3% 2.4% B, NC, W, NA, CRO B, NC, W, N, CRO Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 44.6 3950 5.16E+07 44.1 3724 5.56E+07 1.1% 6.1% -7.2% B, C, W, NA, CRO B, C, W, N, CRO Change Including Adhesive


UB, C, NW, NA, FS UB, C, NW, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural

47 3829 5.26E+07 35.6 2640 6.61E+07 32.0% 45.0% -20.4% UB, NC, NW, NA, FS UB, NC, NW, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 33.4 3284 2.57E+07 27.5 2347 2.51E+07 21.5% 39.9% 2.4% UB, NC, W, NA, FS UB, NC, W, N, FS Change Including Adhesive




UB, C, W, NA, FS UB, C, W, N, FS Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 47.3 3501 7.49E+07 36.4 2555 6.61E+07 29.9% 37.0% 13.3% UB, C, NW, NA, CTO UB, C, NW, N, CTO Change Including Adhesive


UB, NC, NW, NA, CTO UB, NC, NW, N, CTO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 22.9 1793 2.48E+07 19.4 1570 2.03E+07 18.0% 14.2% 22.2% UB, NC, W, NA, CTO UB, NC, W, N, CTO Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 29.4 2065 5.03E+07 23.5 1603 4.95E+07 25.1% 28.8% 1.6% UB, C, W, NA, CTO UB, C, W, N, CTO Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 36.7 2549 7.61E+07 28.2 1831 7.94E+07 30.1% 39.2% -4.2% UB, C, NW, NA, CRO UB, C, NW, N, CRO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 31.7 2694 5.31E+07 26.7 1984 6.02E+07 18.7% 35.8% -11.8%

UB, NC, NW, NA, CRO UB, NC, NW, N, CRO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 26.4 2744 2.20E+07 22.6 2086 2.22E+07 16.8% 31.6% -0.9% UB, NC, W, NA, CRO UB, NC, W, N, CRO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 29.4 2516 4.75E+07 25 1931 4.98E+07 17.6% 30.3% -4.6% UB, C, W, NA, CRO UB, C, W, N, CRO Change Including Adhesive





B, NW, NA, FS B, NW, N, FS Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 69 6134 2.23E+07 65 4417 3.27E+07 6.2% 38.9% -31.8%

B, W, NA, FS B, W, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 71.6 6296 2.35E+07 68 4506.5 3.66E+07 5.3% 39.7% -35.8%

UB, NW, NA, FS UB, NW, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 79.2 4631 4.43E+07 46.3 2880 3.21E+07 71.1% 60.8% 38.0%

UB, W, NA, FS UB, W, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 68.6 4272 3.34E+07 54.3 3453 3.68E+07 26.3% 23.7% -9.2%

B, NW, NA, CRO B, NW, N, CRO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 95.3 8373 2.97E+07 49.7 2965 2.85E+07 91.8% 182.4% 4.2%

B, W, NA, CRO B, W, N, CRO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 89.7 7378 3.00E+07 53.8 3059 3.70E+07 66.7% 141.2% -18.9%




B, NW, NA, FS B, NW, N, FS Change Including Adhesive


B, W, NA, FS B, W, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 91.7 11821 2.16E+07 64 5828 2.00E+07 43.3% 102.8% 8.0%


UB, W, NA, FS UB, W, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural

65 5049 2.20E+07 30.4 1732 1.44E+07 113.8% 191.6% 52.8% B, NW, NA, CRO B, NW, N, CRO Change Including Adhesive


B, W, NA, CRO B, W, N, CRO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 72.3 7493 1.89E+07 51.7 4246 1.67E+07 39.8% 76.5% 13.2% UB, NW, NA, CRO UB, NW, N, CRO Change Including Adhesive


UB, W, NA, CRO UB, W, N, CRO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 43.6 2986 1.66E+07 25.3 1405 1.23E+07 72.3% 112.5% 35.0%



Table B.5 - Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without Adhesive*

UB, C, NW, NA, FS UB, C, NW, N, FS Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 49.1 3997 5.56E+07 40.1 2866 6.62E+07 23.5% 39.9% -16.0% UB, NC, NW, NA, FS UB, NC, NW, N, FS Change Including Adhesive


UB, NC, W, NA, FS UB, NC, W, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 42.2 3492 4.64E+07 38.3 2779 5.29E+07 11.9% 27.1% -10.8%

UB, C, W, NA, FS UB, C, W, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 49.3 3501 7.49E+07 36.4 2555 6.61E+07 35.4% 37.0% 13.3% UB, C, NW, NA, CTO UB, C, NW, N, CTO Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 37.4 2591 7.21E+07 27.0 1727 7.03E+07 37.7% 49.5% 9.5% UB, NC, NW, NA, CTO UB, NC, NW, N, CTO Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 22.0 1707 2.31E+07 18.8 1418 1.94E+07 17.0% 21.1% 18.9% UB, NC, W, NA, CTO UB, NC, W, N, CTO Change Including Adhesive


UB, C, W, NA, CTO UB, C, W, N, CTO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 39.0 2731 7.46E+07 29.2 1868 7.07E+07 33.4% 46.1% 7.0% UB, C, NW, NA, CRO UB, C, NW, N, CRO Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 34.7 2792 5.57E+07 28.7 2125 6.44E+07 20.8% 31.7% -13.5% UB, NC, NW, NA, CRO UB, NC, NW, N, CRO Change Including Adhesive

Global Shear Flexural Global Shear Flexural Global Shear Flexural 28.5 2770 2.36E+07 25.9 2296 2.46E+07 10.6% 21.6% -3.8% UB, NC, W, NA, CRO UB, NC, W, N, CRO Change Including Adhesive



Table B.5 - (Cont’d) Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without Adhesive*

UB, C, W, NA, CRO UB, C, W, N, CRO Change Including Adhesive



Table B.6 - Averaged Cyclic Stiffness Comparisons for Specimens 3 and 4 with

and without Adhesive*

B, NW, NA, FS B, NW, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 81.15 9495 2.19E+07 63.65 5015 2.62E+07 28.0% 84.0% -11.6%

B, W, NA, FS B, W, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 81.65 9058 2.26E+07 66 5167 2.83E+07 24.3% 71.3% -13.9%


UB, W, NA, FS UB, W, N, FS Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 66.8 4660 2.77E+07 42.35 2592 2.56E+07 70.1% 107.6% 21.8%

B, NW, NA, CRO B, NW, N, CRO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural 81.35 7779 2.36E+07 49.2 3365 2.27E+07 65.1% 136.6% 4.2%

B, W, NA, CRO B, W, N, CRO Change Including Adhesive Global Shear Flexural Global Shear Flexural Global Shear Flexural

81 7436 2.45E+07 52.75 3652 2.69E+07 53.3% 108.8% -2.9%


Appendix C: Effects of Center Openings on Diaphragm Cyclic Stiffness | 101

Appendix C - Effects of Center Openings on Diaphragm Cyclic

Stiffness

C.1 Introduction

Several diaphragm configurations were tested with an opening in the center of the

diaphragm in order to assess effects of openings in the center of a floor or roof system, such as

would be present for stairs, great rooms, or skylights. Comparisons between diaphragm

configurations with openings in the center and those with full sheathing are provided in this

section to determine potential reductions in cyclic stiffness caused by the openings. Test

configurations with center openings were performed for Specimens 1, 2, 3 and 4. Specimens 5

and 6 were only tested with full sheathing or corner openings and are not included in the

following comparisons. All test configurations for Specimen 1 were performed in the unblocked

condition.

C.2 Comparisons of Center Opening Effects

Presented below are tables of comparisons for effects of center openings for Specimens 1,

2, 3 and 4, and averaged comparisons for Specimens 1 and 2, and for Specimens 3 and 4.


Table C.1 - Cyclic Stiffness Comparisons for Specimen 1 with and without Center Openings*

NC, NW, N, CTO NC, NW, N, FS Change with Center Opening

Global Shear Flexural Global Shear Flexural Global Shear Flexural18.1 1266 1.85E+07 29.4 2410 2.61E+07 -38.4% -47.5% -29.1%

C, NW, N, CTO C, NW, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural29.1 1845 5.83E+07 44.5 3091 6.63E+07 -34.6% -40.3% -12.1%

C, W, N, CTO C, W, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural30.2 1904 6.19E+07 48.2 3259 8.32E+07 -37.3% -41.6% -25.6%

NC, W, N, CTO NC, W, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural22.9 1438 4.15E+07 43.7 3145 5.83E+07 -47.6% -54.3% -28.8% NC, NW, NA, CTO NC, NW, NA, FS Change with Center Opening

Global Shear Flexural Global Shear Flexural Global Shear Flexural21 1622 2.14E+07 35.4 3234 2.81E+07 -40.7% -49.9% -23.8% C, NW, NA, CTO C, NW, NA, FS Change with Center Opening

Global Shear Flexural Global Shear Flexural Global Shear Flexural42.6 2894 8.72E+07 51.2 4166 5.86E+07 -16.8% -30.5% 48.8%

C, W, NA, CTO C, W, NA, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural41.3 2913 7.31E+07 51.3 4055 6.32E+07 -19.5% -28.2% 15.7%

NC, W, NA, CTO NC, W, NA, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural29.9 2193 4.06E+07 43.3 3645 4.34E+07 -30.9% -39.8% -6.5%




B, C, NW, N, CTO B, C, NW, N, FS Change with Center Opening

Global Shear Flexural Global Shear Flexural Global Shear Flexural34.5 2419 5.55E+07 66.2 6183 5.28E+07 -47.9% -60.9% 5.1% B, NC, NW, N, CTO B, NC, NW, N, FS Change with Center Opening

Global Shear Flexural Global Shear Flexural Global Shear Flexural24.3 2039 2.23E+07 55.5 5626.5 3.82E+07 -56.2% -63.8% -41.6%

B, NC, W, N, CTO B, NC, W, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural31.2 2174 4.66E+07 65.3 6002 5.29E+07 -52.2% -63.8% -11.9%

B, C, W, N, CTO B, C, W, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural36.9 2489 6.30E+07 71.8 6386.5 6.21E+07 -48.6% -61.0% 1.4% B, C, NW, NA, CTO B, C, NW, NA, FS Change with Center Opening

Global Shear Flexural Global Shear Flexural Global Shear Flexural38.7 2990 4.96E+07 67.5 6185.5 5.47E+07 -42.7% -51.7% -9.3% B, NC, NW, NA, CTO B, NC, NW, NA, FS Change with Center Opening

Global Shear Flexural Global Shear Flexural Global Shear Flexural25.9 2244 2.32E+07 46.4 4691.5 3.13E+07 -44.2% -52.2% -25.9% B, NC, W, NA, CTO B, NC, W, NA, FS Change with Center Opening


B, C, W, NA, CTO B, C, W, NA, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural41.3 3082 6.36E+07 67.9 6086 5.97E+07 -39.2% -49.4% 6.5% UB, C, NW, N, CTO UB, C, NW, N, FS Change with Center Opening

Global Shear Flexural Global Shear Flexural Global Shear Flexural24.9 1609 8.22E+07 35.6 2640 6.61E+07 -30.1% -39.1% 24.4% UB, NC, NW, N, CTO UB, NC, NW, N, FS Change with Center Opening

Global Shear Flexural Global Shear Flexural Global Shear Flexural19.4 1570 2.03E+07 27.5 2347 2.51E+07 -29.5% -33.1% -19.1% UB, NC, W, N, CTO UB, NC, W, N, FS Change with Center Opening


UB, C, W, N, CTO UB, C, W, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural28.2 1831 7.94E+07 36.4 2555 6.61E+07 -22.5% -28.3% 20.1%


Table C.2 - (Cont’d) Cyclic Stiffness Comparisons for Specimen 2 with and without Center Openings*

UB, C, NW, NA, CTO UB, C, NW, NA, FS Change with Center Opening

Global Shear Flexural Global Shear Flexural Global Shear Flexural32.1 2288 5.70E+07 47 3829 5.26E+07 -31.7% -40.2% 8.4% UB, NC, NW, NA, CTO UB, NC, NW, NA, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural22.9 1793 2.48E+07 33.4 3284 2.57E+07 -31.4% -45.4% -3.5% UB, NC, W, NA, CTO UB, NC, W, NA, FS Change with Center Opening

Global Shear Flexural Global Shear Flexural Global Shear Flexural29.4 2065 5.03E+07 41 3338 4.94E+07 -28.3% -38.1% 1.8% UB, C, W, NA, CTO UB, C, W, NA, FS Change with Center Opening


*B = Blocked, UB = Unblocked, C = with Chords, NC = no Chords, W = with Walls, NW = no Walls, N = Nailed only, NA = Nails and Adhesive, FS = Fully Sheathed, CRO = Corner Opening, CTO = Center Opening, Global Stiffness measured in kip/inch, Shear Stiffness measured in kip, and Flexural Stiffness measured in kip-inch2. Table C.3 - Cyclic Stiffness Comparisons for Specimen 3 with and without Center

Openings*

B, NW, N, CTO B, NW, N, FS Change with Center Opening Global Shear Flexural Global Shear Flexural Global Shear Flexural 35.3 2006 3.53E+07 65 4417 3.27E+07 -45.7% -54.6% 8.0%

B, W, N, CTO B, W, N, FS Change with Center Opening Global Shear Flexural Global Shear Flexural Global Shear Flexural 39.6 2388 3.02E+07 68 4507 3.66E+07 -41.8% -47.0% -17.5%

UB, NW, N, CTO UB, NW, N, FS Change with Center Opening Global Shear Flexural Global Shear Flexural Global Shear Flexural 24.1 996 2.62E+07 46.3 2880 3.21E+07 -47.9% -65.4% -18.4%

UB, W, N, CTO UB, W, N, FS Change with Center Opening Global Shear Flexural Global Shear Flexural Global Shear Flexural 29.1 1347 2.91E+07 54.3 3453 3.68E+07 -46.4% -61.0% -20.9%




B, NW, N, CTO B, NW, N, FS Change with Center Opening


B, W, N, CTO B, W, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural34.6 2160 1.39E+07 64 5828 2.00E+07 -45.9% -62.9% -30.5%

UB, NW, N, CTO UB, NW, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural20.5 1058 1.10E+07 26.6 1418 1.37E+07 -22.9% -25.4% -19.7%

UB, W, N, CTO UB, W, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural24.1 1276 1.23E+07 30.4 1732 1.44E+07 -20.7% -26.3% -14.6%



Table C.5 - Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without Center Openings*

UB, C, NW, N, CTO UB, C, NW, N, FS Change with Center Opening


UB, NC, NW, N, CTO UB, NC, NW, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural18.8 1418 1.94E+07 28.5 2379 2.6E+07 -33.9% -40.3% -24.1%

UB, NC, W, N, CTO UB, NC, W, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural23.2 1520 4.55E+07 38.3 2779 5.3E+07 -38.1% -43.9% -12.3%

UB, C, W, N, CTO UB, C, W, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural29.2 1867 7.07E+07 42.3 2907 7.5E+07 -29.9% -35.0% -2.7%

UB, C, NW, NA, CTO UB, C, NW, NA, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural37.4 2591 7.21E+07 49.1 3997 5.6E+07 -24.2% -35.4% 28.6% UB, NC, NW, NA, CTO UB, NC, NW, NA, FS Change with Center Opening


UB, NC, W, NA, CTO UB, NC, W, NA, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural29.7 2129 4.55E+07 42.2 3492 4.6E+07 -29.6% -39.0% -2.3%

UB, C, W, NA, CTO UB, C, W, NA, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural39.0 2731 7.46E+07 49.3 3778 6.9E+07 -21.0% -27.7% 8.6%



Table C.6 - Averaged Cyclic Stiffness Comparisons for Specimens 3 and 4 with and without Center Openings*

B, NW, N, CTO B, NW, N, FS Change with Center Opening


B, W, N, CTO B, W, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 37.1 2274 2.21E+07 66.0 5167 2.83E+07 -43.9% -55.0% -24.0%

UB, NW, N, CTO UB, NW, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 22.3 1027 1.86E+07 36.5 2149 2.29E+07 -35.4% -45.4% -19.0%

UB, W, N, CTO UB, W, N, FS Change with Center OpeningGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 26.6 1312 2.07E+07 42.4 2592 2.56E+07 -33.6% -43.6% -17.8%



Appendix D: Effects of Corner Openings on Diaphragm Cyclic Stiffness | 109

Appendix D - Effects of Corner Openings on Diaphragm Cyclic

Stiffness

D.1 Introduction

Several diaphragm configurations were tested with an opening in the corner of the

diaphragm in order to assess effects of openings in a floor system, such as would be present for

stairs. Full sets of tabulated comparisons between diaphragm configurations with openings in the

corner and those with full sheathing are provided in this appendix. Test configurations with

corner openings were performed for all specimens. All test configurations for Specimen 1 were

performed in the unblocked condition and all test configurations for Specimens 5 and 6 were

conducted in the blocked condition.

D.2 Comparisons of Corner Opening Effects

Presented below are tables of comparisons for effects of corner openings for all

specimens, and averaged comparisons for Specimens 1 and 2, Specimens 3 and 4, and for

Specimens 5 and 6.


Table D.1 - Cyclic Stiffness Comparisons for Specimen 1 with and without Corner Openings*

NC, NW, N, CRO NC, NW, N, FS Change with Corner Opening

Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural29.2 3369 1642 2.69E+07 29.4 2608 2212 2.61E+07 -0.7% 29.2% -25.8% 3.1%

C, NW, N, CRO C, NW, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural30.7 3098 1432 6.86E+07 44.5 3003 3179 6.63E+07 -31.0% 3.2% -55.0% 3.5%

C, W, N, CRO C, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural

33 3183 1573 7.60E+07 48.2 3193 3324 8.32E+07 -31.5% -0.3% -52.7% -8.7% NC, W, N, CRO NC, W, N, FS Change with Corner Opening

Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural37.5 3347 1858 8.31E+07 43.7 3140 3150 5.83E+07 -14.2% 6.6% -41.0% 42.5%

NC, NW, NA, CRO NC, NW, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural30.5 3559 2031 2.51E+07 35.4 3535 2933 2.81E+07 -13.8% 0.7% -30.8% -10.7%

C, NW, NA, CRO C, NW, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural37.7 3735 2043 5.82E+07 51.2 4332 3999 5.86E+07 -26.4% -13.8% -48.9% -0.7%

C, W, NA, CRO C, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural39.5 3973 2064 7.27E+07 51.3 4226 3883 6.32E+07 -23.0% -6.0% -46.8% 15.0%

NC, W, NA, CRO NC, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural35.5 3685 2067 4.44E+07 43.3 3967 3323 4.34E+07 -18.0% -7.1% -37.8% 2.3%




B, NC, NW, N, CRO B, NC, NW, N, FS Change with Corner Opening

Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural38.6 5028 2824 2.93E+07 55.5 5334 5919 3.82E+07 -30.5% -5.7% -52.3% -23.3%

B, C, NW, N, CRO B, C, NW, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural44.5 5368 2519 5.17E+07 66.2 6179 6187 5.28E+07 -32.8% -13.1% -59.3% -2.1%

B, C, W, N, CRO B, C, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural46.7 5378 2643 5.72E+07 71.8 6421 6352 6.21E+07 -35.0% -16.2% -58.4% -7.9%

B, NC, W, N, CRO B, NC, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural44.1 4942 2506 5.56E+07 65.3 5910 6094 5.29E+07 -32.5% -16.4% -58.9% 5.1%

UB, NC, NW, N, CRO UB, NC, NW, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural22.6 2841 1330 2.22E+07 27.5 2636 2058 2.51E+07 -17.8% 7.8% -35.4% -11.6%

UB, C, NW, N, CRO UB, C, NW, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural26.7 2753 1215 6.02E+07 35.6 3082 2198 6.61E+07 -25.0% -10.7% -44.7% -8.9%

UB, C, W, N, CRO UB, C, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural27.9 2746 1275 6.85E+07 36.4 2896 2214 6.61E+07 -23.4% -5.2% -42.4% 3.6%

UB, NC, W, N, CRO UB, NC, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural

25 2698 1164 4.98E+07 32.9 2738 2088 4.75E+07 -24.0% -1.5% -44.3% 4.8% B, NC, NW, NA, CRO B, NC, NW, NA, FS Change with Corner Opening


B, C, NW, NA, CRO B, C, NW, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural47.9 5880 2557 5.72E+07 67.5 6375 5996 5.47E+07 -29.0% -7.8% -57.4% 4.6%

B, C, W, NA, CRO B, C, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural

51 6171 2684 6.60E+07 67.9 6723 5449 5.97E+07 -24.9% -8.2% -50.7% 10.6%


Table D.2 - (Cont’d) Cyclic Stiffness Comparisons for Specimen 2 with and without Corner Openings*

B, NC, W, NA, CRO B, NC, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural44.6 5480 2420 5.16E+07 54.9 5441 4757 4.36E+07 -18.8% 0.7% -49.1% 18.3%

UB, NC, NW, NA, CRO UB, NC, NW, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural26.4 3841 1646 2.20E+07 33.4 3999 2569 2.57E+07 -21.0% -4.0% -35.9% -14.4%

UB, C, NW, NA, CRO UB, C, NW, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural31.7 3883 1505 5.31E+07 47 4575 3083 5.26E+07 -32.6% -15.1% -51.2% 1.0%

UB, C, W, NA, CRO UB, C, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural33.3 3770 1564 6.73E+07 47.3 4110 2892 7.49E+07 -29.6% -8.3% -45.9% -10.1%

UB, NC, W, NA, CRO UB, NC, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural29.4 3605 1426 4.75E+07 41 4076 2600 4.94E+07 -28.3% -11.6% -45.2% -3.8%




B, NW, N, CRO B, NW, N, FS Change with Corner Opening

Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural49.7 1801 4129 2.58E+07 65 4249 4585 3.27E+07 -23.5% -57.6% -9.9% -21.1%

B, W, N, CRO B, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural53.8 1784 4334 3.70E+07 68 4273 4740 3.66E+07 -20.9% -58.2% -8.6% 1.1%

UB, NW, N, CRO UB, NW, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural

42 1675 2536 2.59E+07 46.3 3287 2473 3.21E+07 -9.3% -49.0% 2.5% -19.3%UB, W, N, CRO UB, W, N, FS Change with Corner Opening


B, NW, NA, CRO B, NW, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural95.3 4668 12078 2.97E+07 69 6617 5651 2.23E+07 38.1% -29.5% 113.7% 33.2%

B, W, NA, CRO B, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural89.7 4174 10582 3.00E+07 71.6 6871 5720 2.35E+07 25.3% -39.3% 85.0% 27.7%






B, W, N, CRO B, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural51.7 2691 5800 1.67E+07 64 5908 5747 2.00E+07 -19.2% -54.5% 0.9% -16.5%

UB, NW, N, CRO UB, NW, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural22.3 962 1375 1.13E+07 26.6 1430 1406 1.37E+07 -16.2% -32.7% -2.2% -17.5%

UB, W, N, CRO UB, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural25.3 1122 1688 1.23E+07 30.4 1759 1704 1.44E+07 -16.8% -36.2% -0.9% -14.6%

B, NW, NA, CRO B, NW, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural67.4 4389 9980 1.75E+07 91.7 12337 11305 2.16E+07 -26.5% -64.4% -11.7% -19.0%

B, W, NA, CRO B, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural72.3 4754 10232 1.89E+07 93.3 15027 10686 2.14E+07 -22.5% -68.4% -4.2% -11.7%

UB, NW, NA, CRO UB, NW, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural43.2 2361 3679 1.64E+07 54.9 4169 4070 1.83E+07 -21.3% -43.4% -9.6% -10.4%

UB, W, NA, CRO UB, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural43.6 2306 3666 1.66E+07 65 5426 4671 2.20E+07 -32.9% -57.5% -21.5% -24.5%




B, NW, C, N, CRO B, NW, C, N, FS Change with Corner Opening

Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural8.4 833 3409 5.49E+07 9.4 1353 2104 6.82E+07 -10.6% -38.4% 62.0% -19.5%

B, W, C, N, CRO B, W, C, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural

9.2 812 3443 7.94E+07 11.7 1561 2482 1.02E+08 -21.4% -48.0% 38.7% -22.3%

*B = Blocked, UB = Unblocked, C = with Chords, NC = no Chords, W = with Walls, NW = no Walls, N = Nailed only, NA = Nails and Adhesive, FS = Fully Sheathed, CRO = Corner Opening, CTO = Center Opening, Global Stiffness measured in kip/inch, Shear Stiffness measured in kip, and Flexural Stiffness measured in kip-inch2. Table D.6 - Cyclic Stiffness Comparisons for Specimen 6 with and without Corner

Openings*

B, NW, C, N, CRO B, NW, C, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural

4.2 331 994 8.61E+07 5.7 682 846 8.02E+07 -26.3% -51.5% 17.5% 7.4% B, W, C, N, CRO B, W, C, N, FS Change with Corner Opening




Table D.7 - Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without Corner Openings*

UB, NC, NW, N, CRO UB, NC, NW, N, FS Change with Corner Opening

Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural25.9 3105 1486 2.46E+07 28.5 2622 2135 2.56E+07 -9.2% 18.5% -30.6% -4.2%

UB, C, NW, N, CRO UB, C, NW, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural28.7 2926 1324 6.44E+07 40.1 3043 2689 6.62E+07 -28.0% -3.8% -49.8% -2.7%

UB, C, W, N, CRO UB, C, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural30.45 2965 1424 7.23E+07 42.3 3045 2769 7.47E+07 -27.4% -2.7% -47.5% -2.5%

UB, NC, W, N, CRO UB, NC, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural31.25 3023 1511 6.65E+07 38.3 2939 2619 5.29E+07 -19.1% 2.6% -42.6% 23.7%

UB, NC, NW, NA, CRO UB, NC, NW, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural28.45 3700 1839 2.36E+07 34.4 3767 2751 2.69E+07 -17.4% -1.6% -33.3% -12.5%

UB, C, NW, NA, CRO UB, C, NW, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural34.7 3809 1774 5.57E+07 49.1 4454 3541 5.56E+07 -29.5% -14.5% -50.0% 0.1%

UB, C, W, NA, CRO UB, C, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural36.4 3872 1814 7.00E+07 49.3 4168 3388 6.91E+07 -26.3% -7.1% -46.4% 2.4%

UB, NC, W, NA, CRO UB, NC, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural32.45 3645 1747 4.60E+07 42.2 4022 2962 4.64E+07 -23.2% -9.3% -41.5% -0.8%






B, W, N, CRO B, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural52.8 2238 5067 2.69E+07 66.0 5091 5244 2.83E+07 -20.1% -56.4% -3.8% -7.7%

UB, NW, N, CRO UB, NW, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural32.2 1319 1956 1.86E+07 36.5 2359 1940 2.29E+07 -12.7% -40.9% 0.2% -18.4%

UB, W, N, CRO UB, W, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural36.3 1599 2201 2.16E+07 42.4 2930 2255 2.56E+07 -14.8% -42.8% -2.1% -15.3%

B, NW, NA, CRO B, NW, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural81.4 4529 11029 2.36E+07 80.4 9477 8478 2.20E+07 5.8% -46.9% 51.0% 7.1%

B, W, NA, CRO B, W, NA, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural81.0 4464 10407 2.45E+07 82.5 10949 8203 2.25E+07 1.4% -53.8% 40.4% 8.0%




B, NW, C, N, CRO B, NW, C, N, FS Change with Corner Opening


B, W, C, N, CRO B, W, C, N, FS Change with Corner Opening Global L Shear R Shear Flexural Global L Shear R Shear Flexural Global L Shear R Shear Flexural

6.9 590 2237 9.05E+07 9.0 1153 1702 1.03E+08 -25.0% -49.4% 25.3% -12.0%


Appendix E: Effects of Chords on Diaphragm Cyclic Stiffness | 119

Appendix E - Effects of Chords on Diaphragm Cyclic Stiffness

E.1 Introduction

Several configurations were tested with and without chords in order to assess the effects

of including designated chords with regard to cyclic stiffness. Comprehensive comparisons

between diaphragm configurations with chords and without chords are provided in this appendix.

Test configurations with and without chords were performed for Specimens 1, 2, 5 and 6. All

test configurations for Specimen 1 were performed in the unblocked condition and all test

configurations for Specimens 5 and 6 were conducted in the blocked condition.

E.2 Comparisons of Chord Effects

Presented below are tables of comparisons for effects of chords for Specimens 1, 2, 5, and

6, and averaged comparisons for Specimens 1 and 2, and for Specimens 5 and 6.


Table E.1 - Cyclic Stiffness Comparisons for Specimen 1 with and without Chords*

C, NW, NA, CRO NC, NW, NA, CRO Change After Including Chords


C, W, NA, CRO NC, W, NA, CRO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 39.5 3018.5 7.27E+07 35.5 2876 4.44E+07 11.3% 5.0% 63.7%

C, W, N, CRO NC, W, N, CRO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural

33 2378 7.60E+07 37.5 2602.5 8.31E+07 -12.0% -8.6% -8.5% C, NW, N, CRO NC, NW, N, CRO Change After Including Chords

Global Shear Flexural Global Shear Flexural Global Shear Flexural 30.7 2265 6.86E+07 29.2 2505.5 2.69E+07 5.1% -9.6% 155.0%

C, W, N, FS NC, W, N, FS Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 48.2 3258.5 8.32E+07 43.7 3145 5.83E+07 10.3% 3.6% 42.7%

C, NW, N, FS NC, NW, N, FS Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 44.5 3091 6.63E+07 29.4 2410 2.61E+07 51.4% 28.3% 154.0%

C, NW, NA, FS NC, NW, NA, FS Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 51.2 4165.5 5.86E+07 35.4 3234 2.81E+07 44.6% 28.8% 108.5%

C, W, NA, FS NC, W, NA, FS Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 51.3 4054.5 6.32E+07 43.3 3645 4.34E+07 18.5% 11.2% 45.6%

C, NW, N, CTO NC, NW, N, CTO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 29.1 1845 5.83E+07 18.1 1266 1.85E+07 60.8% 45.7% 215.1%

C, W, N, CTO NC, W, N, CTO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 30.2 1903.5 6.19E+07 22.9 1437.5 4.15E+07 31.9% 32.4% 49.2%

C, NW, NA, CTO NC, NW, NA, CTO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 42.6 2894 8.72E+07 21 1621.5 2.14E+07 102.9% 78.5% 307.5%


Table E.1 - (Cont’d) Cyclic Stiffness Comparisons for Specimen 1 with and

without Chords*

C, W, NA, CTO NC, W, NA, CTO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 41.3 2912.5 7.31E+07 29.9 2193 4.06E+07 38.1% 32.8% 80.0%



B, C, NW, NA, FS B, NC, NW, NA, FS Change After Including Chords

Global Shear Flexural Global Shear Flexural Global Shear Flexural 67.5 6185.5 5.47E+07 46.4 4691.5 3.13E+07 45.5% 31.8% 74.8%

B, C, W, NA, FS B, NC, W, NA, FS Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 67.9 6086 5.97E+07 54.9 5099 4.36E+07 23.7% 19.4% 36.9%

B, C, W, N, FS B, NC, W, N, FS Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 71.8 6386.5 6.21E+07 65.3 6002 5.29E+07 10.0% 6.4% 17.4%

B, C, NW, N, FS B, NC, NW, N, FS Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 66.2 6183 5.28E+07 55.5 5626.5 3.82E+07 19.3% 9.9% 38.2%

B, C, NW, NA, CTO B, NC, NW, NA, CTO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 38.7 2989.5 4.96E+07 25.9 2244 2.32E+07 49.4% 33.2% 113.8%

B, C, W, NA, CTO B, NC, W, NA, CTO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 41.3 3082 6.36E+07 33.9 2599.5 4.56E+07 21.8% 18.6% 39.5%

B, C, W, N, CTO B, NC, W, N, CTO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 36.9 2488.5 6.30E+07 31.2 2173.5 4.66E+07 18.3% 14.5% 35.2%

B, C, NW, N, CTO B, NC, NW, N, CTO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 34.5 2419 5.55E+07 24.3 2038.5 2.23E+07 42.0% 18.7% 148.9%


Table E.2 - (Cont’d) Cyclic Stiffness Comparisons for Specimen 2 with and without Chords*

B, C, NW, NA, CRO B, NC, NW, NA, CRO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 47.9 4218.5 5.72E+07 37.4 3598.5 3.00E+07 28.1% 17.2% 90.7%

B, C, W, NA, CRO B, NC, W, NA, CRO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

51 4427.5 6.60E+07 44.6 3950 5.16E+07 14.3% 12.1% 27.9% B, C, W, N, CRO B, NC, W, N, CRO Change After Including Chords

Global Shear Flexural Global Shear Flexural Global Shear Flexural 46.7 3920.5 5.72E+07 44.1 3724 5.56E+07 5.9% 5.3% 2.9%

B, C, NW, N, CRO B, NC, NW, N, CRO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 44.5 3943.5 5.17E+07 38.6 3926 2.93E+07 15.3% 0.4% 76.5%

UB, C, NW, NA, FS UB, NC, NW, NA, FS Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

47 3829 5.26E+07 33.4 3284 2.57E+07 40.7% 16.6% 104.7% UB, C, W, NA, FS UB, NC, W, NA, FS Change After Including Chords

Global Shear Flexural Global Shear Flexural Global Shear Flexural 47.3 3501 7.49E+07 41 3338 4.94E+07 15.4% 4.9% 51.6%

UB, C, W, N, FS UB, NC, W, N, FS Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 36.4 2555 6.61E+07 32.9 2413 4.75E+07 10.6% 5.9% 39.2%

UB, C, NW, N, FS UB, NC, NW, N, FS Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 35.6 2640 6.61E+07 27.5 2347 2.51E+07 29.5% 12.5% 163.3%

UB, C, NW, NA, CTO UB, NC, NW, NA, CTO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 32.1 2288 5.70E+07 22.9 1792.5 2.48E+07 40.2% 27.6% 129.8%

UB, C, W, NA, CTO UB, NC, W, NA, CTO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 36.7 2548.5 7.61E+07 29.4 2065 5.03E+07 24.8% 23.4% 51.3%

UB, C, W, N, CTO UB, NC, W, N, CTO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 28.2 1831 7.94E+07 23.5 1603 4.95E+07 20.0% 14.2% 60.4%


Table E.2 - (Cont’d) Cyclic Stiffness Comparisons for Specimen 2 with and without Chords*

UB, C, NW, N, CTO UB, NC, NW, N, CTO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 24.9 1609 8.22E+07 19.4 1570 2.03E+07 28.4% 2.5% 304.9%

UB, C, NW, NA, CRO UB, NC, NW, NA, CRO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 31.7 2694 5.31E+07 26.4 2744 2.20E+07 20.1% -1.8% 141.4%

UB, C, W, NA, CRO UB, NC, W, NA, CRO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 33.3 2667 6.73E+07 29.4 2516 4.75E+07 13.3% 6.0% 41.7%

UB, C, W, N, CRO UB, NC, W, N, CRO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 27.9 2011 6.85E+07 25 1931 4.98E+07 11.6% 4.1% 37.6%

UB, C, NW, N, CRO UB, NC, NW, N, CRO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 26.7 1984 6.02E+07 22.6 2086 2.22E+07 18.1% -4.9% 171.2%




B, C, NW, N, FS B, NC, NW, N, FS Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

9.4 1728.5 6.82E+07 4 2010 1.22E+07 135.0% -14.0% 459.0% B, C, W, N, FS B, NC, W, N, FS Change After Including Chords

Global Shear Flexural Global Shear Flexural Global Shear Flexural 11.7 2021.5 1.02E+08 8.8 1891 4.84E+07 33.0% 6.9% 111.2%



B, C, NW, N, FS B, NC, NW, N, FS Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

5.7 764 8.02E+07 3.4 996 1.25E+07 67.6% -23.3% 541.6% B, C, W, N, FS B, NC, W, N, FS Change After Including Chords

Global Shear Flexural Global Shear Flexural Global Shear Flexural 6.3 833 1.03E+08 5.1 850 3.52E+07 23.5% -1.9% 193.2%



Table E.5 - Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without Chords*

UB, C, NW, NA, FS UB, NC, NW, NA, FS Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 49.1 3997 5.56E+07 34.4 3259 2.69E+07 42.7% 22.7% 106.6%

UB, C, W, NA, FS UB, NC, W, NA, FS Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 49.3 3778 6.91E+07 42.2 3492 4.64E+07 16.9% 8.1% 48.6%

UB, C, W, N, FS UB, NC, W, N, FS Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 42.3 2907 7.47E+07 38.3 2779 5.29E+07 10.5% 4.7% 40.9%

UB, C, NW, N, FS UB, NC, NW, N, FS Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 40.1 2866 6.62E+07 28.5 2379 2.56E+07 40.4% 20.4% 158.7%

UB, C, NW, NA, CTO UB, NC, NW, NA, CTO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 37.4 2591 7.21E+07 22.0 1707 2.31E+07 71.5% 53.1% 218.7%

UB, C, W, NA, CTO UB, NC, W, NA, CTO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 39.0 2731 7.46E+07 29.7 2129 4.55E+07 31.5% 28.1% 65.7%

UB, C, W, N, CTO UB, NC, W, N, CTO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 29.2 1867 7.07E+07 23.2 1520 4.55E+07 25.9% 23.3% 54.8%

UB, C, NW, N, CTO UB, NC, NW, N, CTO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 27.0 1727 7.03E+07 18.8 1418 1.94E+07 44.6% 24.1% 260.0%

UB, C, NW, NA, CRO UB, NC, NW, NA, CRO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 34.7 2792 5.57E+07 28.5 2769 2.36E+07 21.8% 0.8% 136.6%

UB, C, W, NA, CRO UB, NC, W, NA, CRO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 36.4 2843 7.00E+07 32.5 2696 4.60E+07 12.3% 5.5% 52.7%

UB, C, W, N, CRO UB, NC, W, N, CRO Change After Including Chords Global Shear Flexural Global Shear Flexural Global Shear Flexural 30.5 2194 7.23E+07 31.3 2267 6.65E+07 -0.2% -2.3% 14.5%


Table E.5 - (Cont’d) Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without Chords*

UB, C, NW, N, CRO UB, NC, NW, N, CRO Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural28.7 2125 6.44E+07 25.9 2296 2.46E+07 11.6% -7.2% 163.1%


Table E.6 - Averaged Cyclic Stiffness Comparisons for Specimens 5 and 6 with and without Chords*

B, C, NW, N, FS B, NC, NW, N, FS Change After Including Chords


B, C, W, N, FS B, NC, W, N, FS Change After Including ChordsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

9.0 1427 1.03E+08 7.0 1370 4.18E+07 28.2% 2.5% 152.2%


Appendix F: Effects of Walls on Diaphragm Cyclic Stiffness | 127

Appendix F - Effects of Walls on Diaphragm Cyclic Stiffness

F.1 Introduction

Several diaphragm configurations were tested with and without walls in order to assess

the effects of including walls with regard to cyclic stiffness. A complete set of tabulated

comparisons between diaphragm configurations with walls and without walls is provided in this

appendix. Test configurations with and without walls were performed for all six specimens. All

test configurations for Specimen 1 were performed in the unblocked condition and all test

configurations for Specimens 5 and 6 were conducted in the blocked condition.

F.2 Comparisons of Wall Effects

Presented below are tables of comparisons for effects of walls for all specimens, and

averaged comparisons for Specimens 1 and 2, Specimens 3 and 4, and for Specimens 5 and 6.


Table F.1 - Cyclic Stiffness Comparisons for Specimen 1 with and without Walls*

NC, W, NA, CRO NC, NW, NA, CRO Change After Including Walls Global Shear Flexural Global Shear Flexural Global Shear Flexural 35.5 2876 4.44E+07 30.5 2795 2.51E+07 16.4% 2.9% 76.9%

C, W, NA, CRO C, NW, NA, CRO Change After Including Walls Global Shear Flexural Global Shear Flexural Global Shear Flexural 39.5 3018.5 7.27E+07 37.7 2889 5.82E+07 4.8% 4.5% 24.9%

C, W, N, CRO C, NW, N, CRO Change After Including Walls Global Shear Flexural Global Shear Flexural Global Shear Flexural

33 2378 7.60E+07 30.7 2265 6.86E+07 7.5% 5.0% 10.8% NC, W, N, CRO NC, NW, N, CRO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 37.5 2602.5 8.31E+07 29.2 2505.5 2.69E+07 28.4% 3.9% 208.9%

C, W, N, FS C, NW, N, FS Change After Including Walls Global Shear Flexural Global Shear Flexural Global Shear Flexural 48.2 3258.5 8.32E+07 44.5 3091 6.63E+07 8.3% 5.4% 25.5%

NC, W, N, FS NC, NW, N, FS Change After Including Walls Global Shear Flexural Global Shear Flexural Global Shear Flexural 43.7 3145 5.83E+07 29.4 2410 2.61E+07 48.6% 30.5% 123.4%

NC, W, NA, FS NC, NW, NA, FS Change After Including Walls Global Shear Flexural Global Shear Flexural Global Shear Flexural 43.3 3645 4.34E+07 35.4 3234 2.81E+07 22.3% 12.7% 54.4%

C, W, NA, FS C, NW, NA, FS Change After Including Walls Global Shear Flexural Global Shear Flexural Global Shear Flexural 51.3 4054.5 6.32E+07 51.2 4165.5 5.86E+07 0.2% -2.7% 7.8%

NC, W, N, CTO NC, NW, N, CTO Change After Including Walls Global Shear Flexural Global Shear Flexural Global Shear Flexural 22.9 1437.5 4.15E+07 18.1 1266 1.85E+07 26.5% 13.5% 124.3%

C, W, N, CTO C, NW, N, CTO Change After Including Walls Global Shear Flexural Global Shear Flexural Global Shear Flexural 30.2 1903.5 6.19E+07 29.1 1845 5.83E+07 3.8% 3.2% 6.2%

NC, W, NA, CTO NC, NW, NA, CTO Change After Including Walls Global Shear Flexural Global Shear Flexural Global Shear Flexural 29.9 2193 4.06E+07 21 1621.5 2.14E+07 42.4% 35.2% 89.7%

C, W, NA, CTO C, NW, NA, CTO Change After Including Walls Global Shear Flexural Global Shear Flexural Global Shear Flexural 41.3 2912.5 7.31E+07 42.6 2894 8.72E+07 -3.1% 0.6% -16.2%




B, NC, W, NA, FS B, NC, NW, NA, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 54.9 5099 4.36E+07 46.4 4692 3.13E+07 18.3% 8.7% 39.3%

B, C, W, NA, FS B, C, NW, NA, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 67.9 6086 5.97E+07 67.5 6186 5.47E+07 0.6% -1.6% 9.1%

B, C, W, N, FS B, C, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 71.8 6387 6.21E+07 66.2 6183 5.28E+07 8.5% 3.3% 17.6%

B, NC, W, N, FS B, NC, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 65.3 6002 5.29E+07 55.5 5627 3.82E+07 17.7% 6.7% 38.5% B, NC, W, NA, CTO B, NC, NW, NA, CTO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 33.9 2600 4.56E+07 25.9 2244 2.32E+07 30.9% 15.8% 96.6% B, C, W, NA, CTO B, C, NW, NA, CTO Change After Including Walls


B, C, W, N, CTO B, C, NW, N, CTO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 36.9 2489 6.30E+07 34.5 2419 5.55E+07 7.0% 2.9% 13.5% B, NC, W, N, CTO B, NC, NW, N, CTO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 31.2 2174 4.66E+07 24.3 2039 2.23E+07 28.4% 6.6% 109.0% B, NC, W, NA, CRO B, NC, NW, NA, CRO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 44.6 3950 5.16E+07 37.4 3599 3.00E+07 19.3% 9.8% 72.0% B, C, W, NA, CRO B, C, NW, NA, CRO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 51 4428 6.60E+07 47.9 4219 5.72E+07 6.5% 5.0% 15.4% B, C, W, N, CRO B, C, NW, N, CRO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 46.7 3921 5.72E+07 44.5 3944 5.17E+07 4.9% -0.6% 10.6% B, NC, W, N, CRO B, NC, NW, N, CRO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 44.1 3724 5.56E+07 38.6 3926 2.93E+07 14.2% -5.1% 89.8% UB, NC, W, NA, FS UB, NC, NW, NA, FS Change After Including Walls



Table F.2 - (Cont’d) Cyclic Stiffness Comparisons for Specimen 2 with and without Walls*

UB, C, W, NA, FS UB, C, NW, NA, FS Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 47.3 3501 7.49E+07 47 3829 5.26E+07 0.6% -8.6% 42.4%

UB, C, W, N, FS UB, C, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 36.4 2555 6.61E+07 35.6 2640 6.61E+07 2.2% -3.2% 0.0%

UB, NC, W, N, FS UB, NC, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 32.9 2413 4.75E+07 27.5 2347 2.51E+07 19.6% 2.8% 89.2% UB, NC, W, NA, CTO UB, NC, NW, NA, CTO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 29.4 2065 5.03E+07 22.9 1793 2.48E+07 28.4% 15.2% 102.8% UB, C, W, NA, CTO UB, C, NW, NA, CTO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 36.7 2549 7.61E+07 32.1 2288 5.70E+07 14.3% 11.4% 33.5% UB, C, W, N, CTO UB, C, NW, N, CTO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 28.2 1831 7.94E+07 24.9 1609 8.22E+07 13.3% 13.8% -3.4% UB, NC, W, N, CTO UB, NC, NW, N, CTO Change After Including Walls


UB, NC, W, NA, CRO UB, NC, NW, NA, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 29.4 2516 4.75E+07 26.4 2744 2.20E+07 11.4% -8.3% 115.9% UB, C, W, NA, CRO UB, C, NW, NA, CRO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 33.3 2667 6.73E+07 31.7 2694 5.31E+07 5.0% -1.0% 26.7% UB, C, W, N, CRO UB, C, NW, N, CRO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 27.9 2011 6.85E+07 26.7 1984 6.02E+07 4.5% 1.3% 13.8% UB, NC, W, N, CRO UB, NC, NW, N, CRO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 25 1931 4.98E+07 22.6 2086 2.22E+07 10.6% -7.4% 124.3%




B, W, N, FS B, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

68 4507 3.66E+07 65 4417 3.27E+07 4.6% 2.0% 11.9% B, W, NA, FS B, NW, NA, FS Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 71.6 6296 2.35E+07 69 6134 2.23E+07 3.8% 2.6% 5.4%

UB, W, N, FS UB, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 54.3 3453 3.68E+07 46.3 2880 3.21E+07 17.3% 19.9% 14.6%

UB, W, NA, FS UB, NW, NA, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 68.6 4272 3.34E+07 79.2 4631 4.43E+07 -13.4% -7.8% -24.6%

B, W, N, CRO B, NW, N, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 53.8 3059 3.70E+07 49.7 2965 2.85E+07 8.2% 3.2% 29.8%

B, W, NA, CRO B, NW, NA, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 89.7 7378 3.00E+07 95.3 8373 2.97E+07 -5.9% -11.9% 1.0%

B, W, N3, FS B, NW, N3, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 86.2 6313 3.69E+07 83.9 6425 3.32E+07 2.7% -1.7% 11.1%

UB, W, N3, FS UB, NW, N3, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 58.6 3803 3.51E+07 49.2 3047 3.49E+07 19.1% 24.8% 0.6%

UB, W, N, CRO UB, NW, N, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 47.3 2394 3.09E+07 42 2106 2.59E+07 12.6% 13.7% 19.3%

B, W, N, CTO B, NW, N, CTO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 39.6 2388 3.02E+07 35.3 2006 3.53E+07 12.2% 19.1% -14.4%

UB, W, N, CTO UB, NW, N, CTO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 29.1 1347 2.91E+07 24.1 996 2.62E+07 20.7% 35.2% 11.1%




B, W, N, FS B, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

64 5827.5 2.00E+07 62.3 5613 1.97E+07 2.7% 3.8% 1.5% B, W, NA, FS B, NW, NA, FS Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 91.7 11821 2.16E+07 93.3 12856.5 2.14E+07 -1.7% -8.1% 0.9%

UB, W, N, FS UB, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 30.4 1731.5 1.44E+07 26.6 1418 1.37E+07 14.3% 22.1% 5.1%

UB, W, NA, FS UB, NW, NA, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

65 5048.5 2.20E+07 54.9 4119.5 1.83E+07 18.4% 22.6% 20.2% B, W, N, CRO B, NW, N, CRO Change After Including Walls

Global Shear Flexural Global Shear Flexural Global Shear Flexural 51.7 4245.5 1.67E+07 48.7 3764.5 1.68E+07 6.2% 12.8% -0.6%

B, W, NA, CRO B, NW, NA, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 72.3 7493 1.89E+07 67.4 7184.5 1.75E+07 7.3% 4.3% 8.0%

UB, W, N, CRO UB, NW, N, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 25.3 1405 1.23E+07 22.3 1168.5 1.13E+07 13.5% 20.2% 8.8%

UB, W, NA, CRO UB, NW, NA, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 43.6 2986 1.66E+07 43.2 3020 1.64E+07 0.9% -1.1% 1.2%

B, W, N3, FS B, NW, N3, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 80.1 7969 2.09E+07 77.3 7178 2.14E+07 3.6% 11.0% -2.3%

UB, W, N3, FS UB, NW, N3, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 42.1 2765.5 1.70E+07 38.2 2394 1.63E+07 10.2% 15.5% 4.3%

B, W, N, CTO B, NW, N, CTO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 34.6 2160 1.39E+07 31.8 1933.5 1.37E+07 8.8% 11.7% 1.5%





B, NC, W, N, FS B, NC, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

8.8 1891 4.84E+07 4.0 2010 1.22E+07 120.0% -5.9% 296.7% B, C, W, N, FS B, C, NW, N, FS Change After Including Walls


B, C, W, N, CRO B, C, NW, N, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

9.2 2128 7.94E+07 8.4 2121 5.49E+07 9.5% 0.3% 44.6%

*B = Blocked, UB = Unblocked, C = with Chords, NC = no Chords, W = with Walls, NW = no Walls, N = Nailed only, NA = Nails and Adhesive, FS = Fully Sheathed, CRO = Corner Opening, CTO = Center Opening, Global Stiffness measured in kip/inch, Shear Stiffness measured in kip, and Flexural Stiffness measured in kip-inch2. Table F.6 - Cyclic Stiffness Comparisons for Specimen 6 with and without Walls*

B, NC, W, N, FS B, NC, NW, N, FS Change After Including Walls


B, C, W, N, FS B, C, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

6.3 833 1.03E+08 5.7 764 8.02E+07 10.5% 9.0% 28.7% B, C, W, N, CRO B, C, NW, N, CRO Change After Including Walls




Table F.7 - Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without Walls*

UB, NC, W, NA, FS UB, NC, NW, NA, FS Change After Including Walls


UB, C, W, NA, FS UB, C, NW, NA, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 49.3 3778 6.91E+07 49.1 3997 5.56E+07 0.4% -5.6% 25.1%

UB, C, W, N, FS UB, C, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 42.3 2907 7.47E+07 40.1 2866 6.62E+07 5.3% 1.1% 12.7%

UB, NC, W, N, FS UB, NC, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 38.3 2779 5.29E+07 28.5 2379 2.56E+07 34.1% 16.7% 106.3%

UB, NC, W, NA, CTO UB, NC, NW, NA, CTO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 29.7 2129 4.55E+07 22.0 1707 2.31E+07 35.4% 25.2% 96.3%

UB, C, W, NA, CTO UB, C, NW, NA, CTO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 39.0 2731 7.46E+07 37.4 2591 7.21E+07 5.6% 6.0% 8.7%

UB, C, W, N, CTO UB, C, NW, N, CTO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 29.2 1867 7.07E+07 27.0 1727 7.03E+07 8.5% 8.5% 1.4%

UB, NC, W, N, CTO UB, NC, NW, N, CTO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 23.2 1520 4.55E+07 18.8 1418 1.94E+07 23.8% 7.8% 134.1%

UB, NC, W, NA, CRO UB, NC, NW, NA, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 32.5 2696 4.60E+07 28.5 2769 2.36E+07 13.9% -2.7% 96.4%

UB, C, W, NA, CRO UB, C, NW, NA, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 36.4 2843 7.00E+07 34.7 2792 5.57E+07 4.9% 1.7% 25.8%

UB, C, W, N, CRO UB, C, NW, N, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 30.5 2194 7.23E+07 28.7 2125 6.44E+07 6.0% 3.2% 12.3%


Table F.7 - (Cont’d) Averaged Cyclic Stiffness Comparisons for Specimens 1 and 2 with and without Walls*

UB, NC, W, N, CRO UB, NC, NW, N, CRO Change After Including Walls



Table F.8 - Averaged Cyclic Stiffness Comparisons for Specimens 3 and 4 with and without Walls*

B, W, N, FS B, NW, N, FS Change After Including Walls


B, W, NA, FS B, NW, NA, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 81.7 9058 2.26E+07 81.2 9495 2.19E+07 1.0% -2.7% 3.2%

UB, W, N, FS UB, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 42.4 2592 2.56E+07 36.5 2149 2.29E+07 15.8% 21.0% 9.9%

UB, W, NA, FS UB, NW, NA, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 66.8 4660 2.77E+07 67.1 4375 3.13E+07 2.5% 7.4% -2.2%

B, W, N, CRO B, NW, N, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 52.8 3652 2.69E+07 49.2 3365 2.27E+07 7.2% 8.0% 14.6%

B, W, NA, CRO B, NW, NA, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 81.0 7436 2.45E+07 81.4 7779 2.36E+07 0.7% -3.8% 4.5%

B, W, N3, FS B, NW, N3, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 83.2 7141 2.89E+07 80.6 6801 2.73E+07 3.2% 4.6% 4.4%

UB, W, N3, FS UB, NW, N3, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 50.4 3284 2.61E+07 43.7 2720 2.56E+07 14.7% 20.2% 2.4%

UB, W, N, CRO UB, NW, N, CRO Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural 36.3 1900 2.16E+07 32.2 1637 1.86E+07 13.0% 17.0% 14.1%


Table F.8 - (Cont’d) Averaged Cyclic Stiffness Comparisons for Specimens 3 and 4 with and without Walls*

B, W, N, CTO B, NW, N, CTO Change After Including Walls




Table F.9 - Averaged Cyclic Stiffness Comparisons for Specimens 5 and 6 with and without Corner Openings*

B, NC, W, N, FS B, NC, NW, N, FS Change After Including Walls


B, C, W, N, FS B, C, NW, N, FS Change After Including WallsGlobal Shear Flexural Global Shear Flexural Global Shear Flexural

9.0 1427 1.03E+08 7.6 1246 7.42E+07 17.5% 13.0% 39.3% B, C, W, N, CRO B, C, NW, N, CRO Change After Including Walls



Appendix G: Moisture Content and Density Data | 137

Appendix G - Moisture Content and Density Data

G.1 Introduction

Samples were procured from joists and plywood used to fabricate Specimen 1, and solely

from the joists from Specimens 2, 3, 4, 5, and 6. These samples were analyzed to determine

moisture content and density. Observed measurements included initial mass in grams, dried

mass in grams and amount of water displaced in grams. From these observations, the moisture

content and dried density of each joist (and sheathing for Specimen 1) was determined and

averages were calculated for each of the six specimens. Additionally, moisture meter readings

were recorded at the beginning of various days during testing for Specimens 1, 2, 3, and 4. No

moisture meter readings were recorded for Specimens 5 and 6. This appendix contains tabulated

data for all the moisture content and density data that was collected.


Table G.1 - Specimen 1 Joist Sample Data

Joist # Initial Mass Dried Mass H2O Displaced Moisture Content Density Left to Right (g) (g) (g) : 1g = 1cc H2O (g / cc)

1 2.59 2.14 4.91 0.21 0.44 2 4.24 3.43 7.14 0.24 0.48 3 3.76 3.13 6.69 0.20 0.47 4 4.25 3.48 7.16 0.22 0.49 5 2.80 2.31 5.04 0.21 0.46 6 2.99 2.51 5.73 0.19 0.44 7 3.75 2.99 6.14 0.25 0.49 8 3.36 2.77 5.97 0.21 0.46 9 2.83 2.35 5.09 0.20 0.46 10 3.62 3.00 5.81 0.21 0.52 11 4.10 3.29 6.83 0.25 0.48 12 3.84 3.13 6.31 0.23 0.50 13 4.04 3.30 6.76 0.22 0.49 14 3.54 2.89 6.07 0.22 0.48 15 3.09 2.61 5.69 0.18 0.46

16 3.07 2.57 5.75 0.19 0.45

Average: 0.22 0.47


Table G.2 - Specimen 1 Daily Moisture Meter Readings

Moisture Meter Readings

Joist #

Left to Right % Average

1 14 14 15 14 14 14.2

2 15 14 14 14 14 14.2

3 14 12 12.5 14 12.5 13

4 15 14 14 14 14 14.2

5 14 14 16 14 16 14.8

6 11 13 13 13 14 12.8

7 15 14 15 15 15 14.8

8 13 13.5 14 14 14 13.7

9 12 12.5 12 11.5 12 12

10 15 13 13 13 13.5 13.5

11 14 14 15 15 15 14.6

12 12 13 13.5 13 13 12.9

13 15 14 13 13 13 13.6

14 12 13 13 13 13.5 12.9

15 13 11.5 12.5 12 12 12.2

16 13 12 11 12.5 12.5 12.2

Average: 13.5


Table G.3 - Specimen 1 Plywood Sample Data

Sample # Initial Mass Dried Mass H2O Displaced Moisture Content Density (g) (g) (g) : 1g = 1cc H2O (g / cc) 1 22.67 20.96 34.80 0.08 0.60 2 19.29 17.42 29.05 0.11 0.60 3 20.69 18.12 32.03 0.14 0.57 4 30.25 28.30 46.01 0.07 0.62 5 19.56 18.14 31.03 0.08 0.58 6 21.32 19.30 35.22 0.10 0.55 7 22.30 20.24 37.10 0.10 0.55 8 23.36 21.04 36.63 0.11 0.57 9 21.10 19.51 33.51 0.08 0.58 10 18.59 16.59 28.45 0.12 0.58 11 17.70 15.96 24.64 0.11 0.65 12 22.05 19.36 33.27 0.14 0.58 13 22.01 19.29 32.83 0.14 0.59 14 17.97 16.39 29.38 0.10 0.56 15 27.38 25.47 46.39 0.07 0.55

Average: 0.10 0.58




1 46.39 38.05 79.58 0.22 0.48 2 46.14 37.55 64.70 0.23 0.58 3 45.93 37.22 72.77 0.23 0.51 4 35.81 28.56 62.40 0.25 0.46 5 44.12 37.27 76.33 0.18 0.49 6 48.64 39.15 79.68 0.24 0.49 7 50.74 41.89 76.67 0.21 0.55 8 33.87 28.25 60.25 0.20 0.47 9 35.45 27.72 56.98 0.28 0.49 10 36.09 30.83 67.73 0.17 0.46 11 39.38 33.65 76.79 0.17 0.44 12 35.24 30.11 66.08 0.17 0.46 13 28.16 22.25 52.14 0.27 0.43 14 43.95 35.51 76.04 0.24 0.47 15 36.87 30.47 64.36 0.21 0.47 16 30.40 26.03 66.56 0.17 0.39

Average: 0.22 0.48




Joist #

Left to Right % Average 1 18 17 16 19 20 18 2 17 17 18 17 16 17 3 16 16 15 12 17 15.2 4 16 16 17 20 21 18 5 17 18 16 16 17 16.8 6 19 19 18 16 21 18.6 7 19 16 16 16 17 16.8 8 20 19 14 17 18 17.6 9 21 20 21 20 22 20.8 10 18 20 21 20 16 19 11 20 14 15 14 18 16.2 12 19 21 20 20 17 19.4 13 20 18 19 18 20 19 14 20 19 17 16 19 18.2 15 19 17 16 15 18 17

16 20 17 15 15 16 16.6

Average: 17.8



Joist # Initial Mass Dried Mass H2O Displaced Moisture Content Density Front to Back (g) (g) (g) : 1g = 1cc H2O (g / cc)

1 33.16 25.60 51.68 0.30 0.50 2 32.20 24.67 52.15 0.31 0.47 3 38.59 29.86 49.20 0.29 0.61 4 28.28 21.99 47.04 0.29 0.47 5 25.30 19.74 42.05 0.28 0.47 6 26.96 20.46 50.20 0.32 0.41 7 29.30 22.49 46.77 0.30 0.48 8 25.46 19.30 43.20 0.32 0.45 9 32.70 24.73 49.45 0.32 0.50 10 21.54 16.32 33.68 0.32 0.48 11 18.72 15.60 31.40 0.20 0.50 12 40.37 31.71 69.45 0.27 0.46 13 34.89 29.64 70.87 0.18 0.42 14 39.78 30.02 61.21 0.33 0.49 15 40.40 29.24 61.35 0.38 0.48 16 29.72 23.38 49.85 0.27 0.47

Average: 0.29 0.48




Joist #

Front to Back % Average 1 18 17 20 19 16 18 2 19 20 22 16 18 19 3 20 17 17 18 20 18.4 4 20 21 16 22 17 19.2 5 21 21 20 19 17 19.6 6 18 19 20 16 22 19 7 21 20 19 16 18 18.8 8 20 15 18 20 18 18.2 9 21 19 18 19 16 18.6 10 20 20 20 18 20 19.6 11 19 18 19 15 16 17.4 12 19 15 16 15 18 16.6 13 17 18 20 15 14 16.8 14 18 19 19 16 19 18.2 15 19 22 18 21 23 20.6 16 18 16 17 17 20 17.6

Average: 18.5



Joist # Initial Mass Dried Mass H2O Displaced Moisture Content Density Front to Back (g) (g) (g) : 1g = 1cc H2O (g / cc)

1 59.40 48.27 99.80 0.23 0.48 2 54.70 45.05 117.01 0.21 0.39 3 61.60 51.20 91.25 0.20 0.56 4 76.40 63.16 108.13 0.21 0.58 5 55.70 45.90 97.49 0.21 0.47 6 101.70 82.75 139.36 0.23 0.59 7 64.90 53.11 105.92 0.22 0.50 8 72.60 58.11 106.32 0.25 0.55 9 70.90 57.39 108.95 0.24 0.53 10 82.60 67.72 105.25 0.22 0.64 11 54.90 45.03 100.53 0.22 0.45 12 61.10 49.78 103.35 0.23 0.48 13 60.70 49.03 109.34 0.24 0.45 14 82.90 67.08 111.28 0.24 0.60 15 56.90 44.43 108.17 0.28 0.41 16 65.50 51.49 112.11 0.27 0.46

Average: 0.23 0.51



Moisture Meter Readings Joist #

Front to Back % Average 1 22 20 23 22 19 21.2 2 21 17 24 25 21 21.6 3 25 19 21 21 22 21.6 4 23 25 20 21 21 22 5 20 19 22 23 24 21.6 6 25 23 20 19 26 22.6 7 20 19 18 23 21 20.2 8 26 24 22 23 28 24.6 9 22 24 21 25 22 22.8 10 27 24 23 21 19 22.8 11 21 23 23 19 22 21.6 12 24 22 18 20 21 21 13 20 20 20 19 22 20.2 14 23 25 22 25 21 23.2 15 26 27 23 20 25 24.2 16 28 25 26 22 26 25.4

Average: 22.3




1 15.57 12.30 31.47 0.27 0.39 2 17.73 15.10 28.20 0.17 0.54 3 16.97 14.16 25.53 0.20 0.55 4 15.57 13.77 33.94 0.13 0.41 5 11.80 9.69 19.17 0.22 0.51 6 15.13 12.32 25.84 0.23 0.48 7 15.55 12.15 27.44 0.28 0.44 8 11.70 10.34 21.17 0.13 0.49 9 18.43 14.31 29.07 0.29 0.49 10 17.39 14.06 28.56 0.24 0.49 11 11.62 10.21 24.97 0.14 0.41 12 12.39 10.66 23.37 0.16 0.46 13 14.82 12.58 26.42 0.18 0.48 14 15.43 13.62 23.35 0.13 0.58 15 10.73 9.03 19.00 0.19 0.48 16 11.99 10.21 24.04 0.17 0.42 17 13.39 10.81 28.00 0.24 0.39 18 15.82 12.93 19.05 0.22 0.68 19 22.46 17.85 31.68 0.26 0.56 20 14.10 11.29 25.30 0.25 0.45 21 13.94 11.66 23.27 0.20 0.50 22 16.66 13.49 31.06 0.23 0.43 23 18.40 13.32 29.23 0.38 0.46 24 13.88 11.46 23.61 0.21 0.49 25 13.83 12.01 25.66 0.15 0.47 26 19.04 14.86 31.35 0.28 0.47 27 18.40 13.73 31.54 0.34 0.44 28 19.53 16.40 30.69 0.19 0.53 29 14.18 12.17 24.75 0.17 0.49


Table G.10 - (Cont’d) Specimen 5 Joist Sample Data

30 15.69 13.83 33.38 0.13 0.41 31 16.37 13.56 32.00 0.21 0.42 Average: 0.21 0.48


Sample # Initial Mass Dried Mass H2O Displaced Moisture Content Density Left to Right (g) (g) (g) : 1g = 1cc H2O (g / cc)

1 21.30 18.89 37.06 0.13 0.51 2 23.58 19.56 39.76 0.21 0.49 3 10.71 9.38 22.23 0.14 0.42 4 18.43 16.14 37.40 0.14 0.43 5 18.43 16.14 37.40 0.14 0.43 6 18.50 16.38 35.88 0.13 0.46 7 18.50 16.38 35.88 0.13 0.46 8 26.17 23.16 45.85 0.13 0.51 9 26.17 23.16 45.85 0.13 0.51 10 24.00 19.44 41.64 0.23 0.47 11 24.00 19.44 41.64 0.23 0.47 12 18.95 16.65 35.93 0.14 0.46 13 18.95 16.65 35.93 0.14 0.46 14 18.23 16.01 31.40 0.14 0.51 15 18.23 16.01 31.40 0.14 0.51 16 23.58 19.56 39.76 0.21 0.49 17 15.59 13.71 32.58 0.14 0.42 18 15.59 13.71 32.58 0.14 0.42 19 12.58 11.01 22.38 0.14 0.49 20 12.58 11.01 22.38 0.14 0.49 21 10.72 9.45 17.62 0.13 0.54 22 10.72 9.45 17.62 0.13 0.54 23 25.31 22.03 41.37 0.15 0.53 24 21.30 18.89 37.06 0.13 0.51


Table G.11 - (Cont’d) Specimen 6 Joist Sample Data

25 25.31 22.03 41.37 0.15 0.53 26 19.69 17.29 37.45 0.14 0.46 27 19.69 17.29 37.45 0.14 0.46 28 18.29 16.21 32.46 0.13 0.50 29 18.29 16.21 32.46 0.13 0.50 30 19.68 17.18 37.08 0.15 0.46 31 19.68 17.18 37.08 0.15 0.46 Average: 0.15 0.48


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