FORM 1 CERTIFICATE OF SEISMIC PERFORMANCE ......Campus: UC Berkeley Building Name: Evans Hall CAAN...

Campus: UC BerkeleyBuilding Name: Evans HallCAAN ID: 1790 Auxiliary Building ID: N/A Date: 6/30/2019

This Form 1 (March 26, 2019) is to be used in connection with Guidebook, Version 1.3, Section III.A.3.c-gPage 1

FORM 1CERTIFICATE OF SEISMIC PERFORMANCE LEVEL

☒ UC-Designed & Constructed Facility☐ Campus-Acquired or Leased Facility

BUILDING DATABuilding Name: Evans HallAddress: Core Campus, Berkeley, CA 94720Site location coordinates: Latitude 37.8735 Longitudinal -122.2576

UCOP SEISMIC PERFORMANCE LEVEL (OR “RATING”): VI

ASCE 41-17 Model Building Type:a. Longitudinal Direction: C2: Reinforced Concrete Shear Walls b. Transverse Direction: C2: Reinforced Concrete Shear Walls

Gross Square Footage: 284,362 sq. ft. Number of stories above grade: 11 (also has a partial penthouse not counted as story)Number of basement stories below grade: 1

Year Original Building was Constructed: 1971Original Building Design Code & Year: 1964 UBC Retrofit Building Design Code & Code (if applicable): N/A

Cost to Retrofit: HighFalling Hazards: Low

SITE INFORMATIONSite Class: C Basis: Geologic Hazards and Site Classification, GeoMatrix Plate 2Geologic Hazards: Fault Rupture: No Basis: Earthquake Zones of Required Investigation- Oakland West Quadrangle https://maps.conservation.ca.gov/cgs/informationwarehouse/regulatorymaps/Liquefaction: No Basis: Earthquake Zones of Required Investigation- Oakland West Quadrangle https://maps.conservation.ca.gov/cgs/informationwarehouse/regulatorymaps/Landslide: No Basis: Earthquake Zones of Required Investigation- Oakland West Quadrangle https://maps.conservation.ca.gov/cgs/informationwarehouse/regulatorymaps/

ATTACHMENTSeismic Evaluation: Evans Hall Seismic Options Study (ASCE 41-13 Tier 3)-Draft Report, Degenkolb

Engineers, October 2018



CERTIFICATION & PRESUMPTIVE RATING VERIFICATION STATEMENT

I, Ray Pugliesi, a California-licensed structural engineer, am responsible for the completion of this certificate, and I have no ownership interest in the property identified above. My scope of review to support the completion of this certificate included both of the following (“No” responses must include an explanation):

a) the review of structural drawings indicating that they are as-built or record drawings, or that they otherwise are the basis for the construction of the building: Yes ☐ No

b) visiting the building to verify the observable existing conditions are reasonably consistent with those shown on the structural drawings: Yes ☐ No

Based on my review, I have verified that the UCOP Seismic Performance Level (SPL) is presumptively permitted by the following UC Seismic Program Guidebook provision (choose one of the following):

☐ 1) Contract documents indicate that the original design and construction of the aforementioned building is in accordance with the benchmark design code year (or later) building code seismic design provisions for UBC or IBC listed in Table 1 below.

2) The existing SPL rating is based on an acceptable basis of seismic evaluation completed in 2006 or later.

☐ 3) Contract documents indicate that a comprehensive1 building seismic retrofit design was fully-constructed with an engineered design based on the 1997 UBC/1998 or later CBC, and (choose one of the following):

☐ the retrofit project was completed by the UC campus. Further, the design was based on ground motion parameters, at a minimum, corresponding to BSE-1E (or BSE-R) and BSE-2E (or BSE-C) as defined in ASCE 41, or the full design basis ground motion required in the 1997 UBC/1998 CBC or later for EXISTING buildings, and is presumptively assigned an SPL rating of IV.☐ the retrofit project was completed by the UC campus. Further, the design was based on ground motion parameters, at a minimum, corresponding to BSE-1 (or BSE-1N) and BSE-2 (or BSE-2N) as defined in ASCE 41, or the full design basis ground motion required in the 1997 UBC/1998 or later CBC for NEW buildings, and is presumptively assigned an SPL rating of III.☐ the retrofit project was not completed by the UC campus following UC policies, and is presumptively assigned an SPL rating of IV.

1 A comprehensive retrofit addresses the entire building structural system as indicated by the associated seismic evaluation, as opposed to addressing selective portions of the structural system.



CERTIFICATION SIGNATURE

Raymond S. Pugliesi Senior PrincipalPrint Name Title

S3968 3/31/2020CA Professional Registration No. License Expiration Date

7/8/2019Signature Date

Firm Name, Phone Number, and Address

AFFIX SEAL HERE

Table 1: Benchmark Building Codes and Standards

UBC IBCWood frame, wood shear panels (Types W1 and W2) 1976 2000Wood frame, wood shear panels (Type W1a) 1976 2000Steel moment-resisting frame (Types S1 and S1a) 1997 2000Steel concentrically braced frame (Types S2 and S2a) 1997 2000Steel eccentrically braced frame (Types S2 and S2a) 1988g 2000Buckling-restrained braced frame (Types S2 and S2a) f 2006Metal building frames (Type S3) f 2000Steel frame with concrete shear walls (Type S4) 1994 2000Steel frame with URM infill (Types S5 and S5a) f 2000Steel plate shear wall (Type S6) f 2006Cold-formed steel light-frame construction—shear wall system (Type CFS1) 1997h 2000Cold-formed steel light-frame construction—strap-braced wall system (Type CFS2) f 2003Reinforced concrete moment-resisting frame (Type C1)i 1994 2000Reinforced concrete shear walls (Types C2 and C2a) 1994 2000Concrete frame with URM infill (Types C3 and C3a) f f

Tilt-up concrete (Types PC1 and PC1a) 1997 2000Precast concrete frame (Types PC2 and PC2a) f 2000Reinforced masonry (Type RM1) 1997 2000Reinforced masonry (Type RM2) 1994 2000Unreinforced masonry (Type URM) f f

Unreinforced masonry (Type URMa) f f

Seismic isolation or passive dissipation 1991 2000

Note: UBC = Uniform Building Code . IBC = International Building Code .a Building type refers to one of the common building types defined in Table 3-1 of ASCE 41-17.b Buildings on hillside sites shall not be considered Benchmark Buildings.c not usedd not usede not usedf No benchmark year; buildings shall be evaluated in accordance with Section III.J.

h Cold-formed steel shear walls with wood structural panels only.i Flat slab concrete moment frames shall not be considered Benchmark Buildings.

Building Seismic Design Provisions

g Steel eccentrically braced frames with links adjacent to columns shall comply with the 1994 UBC Emergency Provisions, published September/October 1994, or subsequent requirements.

Building Typea,b

Note: This table has been adapted from ASCE 41-17 Table 3-2. Benchmark Building Codes and Standards for Life Safety Structural Performed at BSE-1E.

Degenkolb Engineers, 415-392-6952, 375 Beale Street, Suite 500San Francisco, CA 94105

S e i s m i c O p t i o n s S t u d yVo l u m e 1 : A p p e n d i x

O c to b e r 2 0 1 8

Ev a n s H a l l U n i ve r s i t y o f C a l i f o r n i a B e r ke l e y

DRAFT

PAGE 1 UC BERKELEYOctober xx, 2018

EVANS HALL SEISMIC OPTIONS STUDYAPPENDIX

AAppendix1 Structural Report2 Basis of Design Cost Estimate34

Cost Estimate Peer Review Summary of Meetings and Minutes

Structural ReportA-1

A-1 Structural Report

UCB Evans Hall, Berkeley, California

Date: April 24, 2018 Degenkolb Job Number B7114006.00

Seismic Options Study

Structural Design Methodology and Criteria For Seismic Analysis and Design

STRUCTURAL DESIGN METHODOLOGY AND CRITERIA FOR SEISMIC ANALYSIS AND DESIGN

UCB EVANS HALL

i April 24, 2018\\sf-data\projects\project.b07\114\b7114007.00\reports\locked\180424rpt_ucb evans hall_deisgn criteria - final.docx

Contents 1.0 Introduction ......................................................................................................... 1

1.1 Design Methodology and Acceptance Criteria .................................................. 1 1.2 General Building Description ............................................................................. 1

1.2.1 Site Description ........................................................................................... 2 1.2.2 Structural Description .................................................................................. 2

1.3 Project Team ..................................................................................................... 3 1.4 Codes, Standards and Documents ................................................................... 3

1.4.1 Design Code and Supporting Documents.................................................... 3 1.5 Definitions ......................................................................................................... 4 1.6 Basic Design Criteria ........................................................................................ 4

1.6.1 Gravity Loads .............................................................................................. 4 1.6.2 Wind Loads .................................................................................................. 4 1.6.3 Seismic Loads ............................................................................................. 4 1.6.4 Load Combinations ...................................................................................... 5 1.6.5 Material Properties ...................................................................................... 5

2.0 Seismic Analysis and Design ............................................................................ 7 2.1 Ground Motion Definition .................................................................................. 7 2.2 Seismic Analysis ............................................................................................... 7

2.2.1 Models for Seismic Analysis ........................................................................ 7 2.2.2 Linear Dynamic Analysis ............................................................................. 7 2.2.3 Nonlinear Response History Model ............................................................. 8 2.2.4 BSE-2E Analysis ....................................................................................... 10 2.2.5 BSE-1E Analysis ....................................................................................... 12

Appendix A: Reference Documents (Under a Separate Cover) Appendix B: Site Specific Seismic Analysis (Under a Separate Cover)

SEISMIC DESIGN CRITERIA UC BERKELEY, EVANS HALL

ii April 24, 2018\\sf-data\projects\project.b07\114\b7114007.00\reports\locked\180424rpt_ucb evans hall_deisgn criteria - final.docx

List of Tables Table 1: Live Loads ...................................................................................................... 4 Table 2: Concrete Material Properties ........................................................................ 5 Table 3: Concrete Reinforcing Steel Material Properties .......................................... 6 Table 4a: Structural Steel Material Properties ........................................................... 6 Table 4b: Bolt Material Properties .............................................................................. 6 Table 5: Component Stiffness Properties .................................................................. 8 Table 6: Component Stiffness Properties .................................................................. 9 Table 7: Load Factor for Critical and Ordinary Force-Controlled Behaviors ........ 11 Table 8: Collapse Prevention Acceptance Criteria for Components ..................... 12 Table 9: Life Safety Acceptance Criteria for Components ..................................... 14


iii April 24, 2018\\sf-data\projects\project.b07\114\b7114007.00\reports\locked\180424rpt_ucb evans hall_deisgn criteria - final.docx

UCB Evans Hall

Structural Design Methodology and Criteria For Seismic Analysis and Design

Version 1.0

April 24, 2018

STRUCTURAL ENGINEERS - DEGENKOLB ENGINEERS Ray Pugliesi, S.E. – Senior Principal Alex Barnes, P.E. – Project Engineer Erik Moore; P.E. – Design Engineer David Lam – Designer Elena Good - Designer


1 April 24, 2018\\sf-data\projects\project.b07\114\b7114007.00\reports\locked\180424rpt_ucb evans hall_deisgn criteria - final.docx

1.0 Introduction

1.1 Design Methodology and Acceptance Criteria This document provides the seismic evaluation design methodology and acceptance criteria for the UCB Evans Hall building in Berkeley. This document serves as the guideline for implementation and review of the seismic evaluation. It describes the seismic analysis procedures including site-specific hazard definition, linear dynamic analysis, nonlinear response history analysis and acceptance criteria for elements of the primary lateral force resisting system as well as secondary elements critical to the building performance. For the detailed seismic evaluation both linear dynamic analysis and nonlinear response history analysis are used to assess the seismic performance of the building in its existing condition, as well as the proposed retrofit procedures. The analysis is based on the Tier 3 nonlinear dynamic procedures found in ASCE 41-17 Seismic Evaluation and Retrofit of Existing Buildings.

1.2 General Building Description UCB Evans Hall is 11 stories tall with a full basement below the ground level, a partial mezzanine between level 1 and level 2 and a partial penthouse level extending above the roof. The typical floor plate is generally rectangular with overall dimensions of approximately 185 feet in the north-south direction by 134 feet in the east-west direction except with the addition of 3 to 4 horizontal steps of roughly 6 feet in and out along the perimeter. An outdoor terrace occurs around the perimeter at level 1 where the façade steps inward. The typical floor-to-floor height is 13 feet 4 inches at levels 2 through 10, a tall-story height of 20 feet occurs at level 1 and 16 feet floor-to-floor at the ground and basement levels. The roof is approximately 156 feet above the ground level with the partial penthouse extending an additional 9 feet above that. An open-air central courtyard occurs at level 9 creating a large opening in the level 10 and roof slabs approximately 50 feet by 50 feet. Evans Hall consists of reinforced concrete slabs, beams, columns and walls. Large steel plate girders are used at level 1 to support discontinuous concrete columns from above, providing a more open floor plan at the ground floor. A partial mezzanine occurs at level 1 in the library carrying book stacks. The foundations are set below the finished basement slab-on-grade approximately 10 feet to accommodate tunnels for mechanical, electrical and plumbing. The foundations are a mix of isolated reinforced concrete spread footings at the interior and continuous strip footings at the exterior. The building was designed in 1967 by Gardner A. Dailey Architects and H. J. Brunnier Associates Structural Engineers to the 1964 Uniform Building Code.



1.2.1 Site Description The building is located on the University of California Berkeley campus between two open lawn areas, the Hearst Mining Circle to the east and the Memorial Glade to the west. Located at Latitude 37.8735 north and Longitude 122.2576 west, this structure is approximately 0.5 km (0.3 miles) from the Hayward Fault, which is capable of producing significant earthquakes with magnitudes greater than 6.0. The site slopes gradually from the east (Hurst Mining Circle) to the west (Memorial Glade) for a total vertical drop of 16 feet over a distance of 134 feet. The nearest adjacent structure is the Sibley Auditorium approximately 50 feet to the north. Woodward-Clyde-Sherard & Associates performed a geotechnical investigation of the site for use in the original design. Based on the site-specific seismic hazard analysis performed by URS Corporation and Pacific Engineering & Analysis the site soil is of majority Franciscan complex sandstone which most closely represents Site Class C.

1.2.2 Structural Description

1.2.2.1 Subgrade Structure The subgrade structure at level 1 and below consists of reinforced concrete foundation walls and pilasters (below columns) along the perimeter at both the ground and basement levels. The basement walls vary from 1 ft. thick to 1 ft. 3 in. thick at the ground and basement floors respectively. Given the sloping site, the ground level daylights on the west side (towards Memorial Glade) which contains punched walls, site stairs and air intake shafts for the basement level below. The exterior foundation walls along the north, south and east sides extend from level1 to below the basement floor where they are supported by continuous reinforced concrete footings. The reinforced concrete utility tunnels located below the basement slab and above the typical footings navigate east to west from the elevator and stair shafts towards the exterior of the building.

1.2.2.2 Gravity Force Resisting System The typical vertical force resisting system at the exterior bays is made up of a 5 in. mild-reinforced slab spanning to 22 in. deep concrete beams at 10 ft. on-center. The beams are supported at the exterior by deep spandrel beams spanning to exterior columns varying in shape. Towards the interior the beams are supported by either concrete shear walls, where occur or 30 in. deep reinforced concrete girders spanning north-south to 28 in. square columns. At the interior bays a 4-1/2 in. reinforced slab over 2 ft. deep pan joists at 4 ft. on-center span between the girders and walls. Both interior and exterior columns are continuous from level 1 to the roof, below level 1 exterior columns are supported by pilasters and interior columns either continue to the foundation or are supported by concrete encased steel columns. In addition, four interior columns at the interior bays are discontinuous at level 1, supported by 5 ft. deep steel plate girders encased in concrete spanning 40 ft. to concrete encased steel columns.



The roof consists of a similar system except with sloping beams at the exterior bays for drainage and a large opening at the interior bays for the courtyard below at level 9.

1.2.2.3 Lateral Force Resisting System Reinforced concrete shear walls are the primary lateral force resisting system varying in thickness from 8 in. to 12 in. The walls are located around stairs and elevators in two main groupings towards the north and south of the overall plan. Extending from the foundation to the roof these walls vary in length and have numerous openings varying in size and location creating many vertical discontinuities. Columns are typically located below discontinuous walls to transfer any overturning forces to the foundation. The typical shear wall foundation consists of a 3-foot deep reinforced concrete bearing type footing. The diaphragm consists of a reinforced concrete slab varying in thickness at each level doweled to the shear walls over their length. All foundation elements are isolated.

1.3 Project Team 1. Owner – University of California Berkeley 2. Architect – Ratcliff Architects 3. Structural Engineer – Degenkolb Engineers

1.4 Codes, Standards and Documents

1.4.1 Design Code and Supporting Documents The relevant design codes and reference standards used for the seismic analysis and retrofit of UCB Evans Hall include:

1. 2016 California Existing Building Code 2. University of California Seismic Safety Policy (UCSSP) – May 22, 2017 3. Reference Standards

a. ASCE Standard ASCE/SEI 41-17 Seismic Evaluation and Retrofit of Existing Buildings

b. ASCE Standard ASCE/SEI 7-16 - Minimum Design Loads for Buildings and Other Structures.

c. ACI 318-14, Building Code Requirements for Structural Concrete. d. ANSI/AISC 341-15– Seismic Provisions for Structural Steel Buildings e. ANSI/AISC 360-15 – Specification for Structural Steel Buildings.

4. Structural Reference Documents a. NIST GCR 17-917-45 – Recommended Modeling Parameters and Acceptance

Criteria for Nonlinear Analysis in Support of Seismic Evaluation, Retrofit, and Design.



b. NIST GCR 17-917-46v1 – Guidelines for Nonlinear Structural Analysis for Design of Buildings Part I – General

c. NEHRP 2015 Recommended Provisions of the Seismic Design of Buildings and Other Structures

1.5 Definitions Definitions and symbols are generally as defined in the references standards and documents.

1.6 Basic Design Criteria

1.6.1 Gravity Loads 1. Dead loads are based on structural and architectural materials existing in the building

including framing, flooring, ceiling, façade, MEP systems, a miscellaneous allowance and other architectural weights.

2. Live loads are taken from ASCE 7 as follows:

Table 1: Live Loads Occupancy or Use Uniform Live Load

Office 50 psf

Classroom 40 psf Lecture Halls (>750 sf and 50 occupants; fixed

seats) 60 psf

Library (stacks) 150 psf

Lobbies and First Floor Corridors 100 psf

Corridors Above First Floor 80 psf

Stairs/Exit ways 100 psf

3. The seismic mass will be taken as defined in ASCE 41, §7.4.1.3.1. Seismic weight

includes total dead loads, minimum 10 psf for partitions and 25% of the library stack live loading.

1.6.2 Wind Loads Wind loads are determined per ASCE 7.

1.6.3 Seismic Loads Seismic loads are determined per ASCE 41.



1.6.4 Load Combinations ASCE 41 load combination per chapter 7, equation (7-3) are used for the nonlinear analysis.

Where is full dead load per as built drawings And 25% of the unreduced live load per ASCE 7-16 And is a snow load that is not considered in this location.

1.6.5 Material Properties Material properties used in the analysis will be as stipulated on the contract drawings and modified by ASCE 41. Because the building is a modern reinforced concrete building with nearly complete construction documents, material testing on the steel and concrete will not be performed. It is the belief of the project team that material testing of the concrete and reinforcement will not yield information that will significantly affect the analysis results. Therefore, the knowledge factor in Section 6.2.4 of ASCE 41 will be taken as 1.0.

1. Concrete Properties Concrete material properties will be as specified on the structural drawings. The concrete strengths specified are typical of concrete of that era and our experience indicates that the nominal compressive strengths specified on the structural drawings are sufficiently conservative lower-bound estimates. The nominal strengths will be translated to expected strength if the analysis indicates the potential for flexural yielding in the mat or walls using a factor of 1.5 as indicated in Table 10-1 of ASCE 41. All concrete is light-weight concrete with a density of 110 pcf per the structural drawings unless noted otherwise below.

Table 2: Concrete Material Properties Structural Component Nominal Compressive

Strength Expected Compressive

Strength

Beams 3,000 psi 4,500 psi

Elevated Slabs 3,000 psi 4,500 psi

Exterior Columns 3,000 psi 4,500 psi

Interior Columns (bounded by lines 2/4 and B/G) 4,500 psi 6,750 psi

Columns below Level 1 (CC5; DD5; EE5; FF5) 4,500 psi 6,750 psi

Exterior Walls 3,000 psi 4,500 psi

Interior Walls (bounded by lines 2/4 and B/G) 4,500 psi 6,750 psi

Foundation Walls 3,000 psi 4,500 psi Basement Slab-on-Grade

and Foundations(1) 3,000 psi 4,500 psi (1) Normal weight concrete with density of 145 pcf



2. Concrete Reinforcement Concrete reinforcing steel properties will be based on the ASTM designation specified on the structural drawings. The reinforcing steel strengths specified are typical of concrete of that era and our experience indicates that the tensile and yield strengths specified on the structural drawings are sufficiently conservative lower-bound estimates. The nominal strengths will be translated to expected strength if the analysis indicates the potential for flexural yielding in the mat or wall using a factor of 1.25 as indicated in Table 10-1 of ASCE 41.

Table 3: Concrete Reinforcing Steel Material Properties

Grade Yield Strength Expected Yield Strength

Tensile Strength

Expected Tensile Strength

A15, Gr. 40 40 ksi 50 ksi 70 ksi 80.5 ksi A432, Gr. 60(1) 60 ksi 75 ksi 90 ksi 105 ksi

(1) Column verticals and special wall reinforcement per the original structural drawings

3. Structural Steel Properties For structural steel, the nominal (lower-bound) material properties will be based on Table 9-1 in ASCE 41 based on the steel ASTM designation specified on the original structural drawings and the shape group the member falls in based on Table 1-1 in the AISCManual of Steel Construction LRFD, 2nd Edition. The nominal strengths will be translated to expected strength through the use of factors found in Table 9-3 in ASCE 41.

Table 4a: Structural Steel Material Properties

Nominal Yield Strength Expected Yield Strength A36, Group 1 44 ksi 49 ksi A36, Group 2 41 ksi 45 ksi A36, Group 3 39 ksi 43 ksi A36, Group 4 37 ksi 41 ksi A441, Group 1 & 2 50 ksi 55 ksi A441, Group 3 46 ksi 50.6 ksi A441, Group 4 & 5 42 ksi 46.2 ksi

Table 4b: Bolt Material Properties

Grade Expected Strength High Strength Bolts A325-X 120 ksi



2.0 Seismic Analysis and Design

2.1 Ground Motion Definition Site-specific response spectrums for both BSE-1E and BSE-2E based on ASCE 41-13 as summarized in a separate document prepared by URS Corporation and Pacific engineering & Analysis titled “2015 Update to the Site-Specific Seismic Hazard Analysis and Development of Seismic Design Ground Motions” dated July 15, 2015. 11 pairs of ground motion acceleration records scaled to the site-specific BSE-1E and BSE-2E spectra as provided by UC Berkeley and summarized in a separate document prepared by Lettis Consultants International, Inc. titled Development of Site-Specific Time Histories for Evans Hall, University of California Berkeley dated March 6, 2018.

2.2 Seismic Analysis

2.2.1 Models for Seismic Analysis Two separate three-dimensional models will be created for seismic analysis, a linear elastic model using ETABS and a nonlinear model using Perform 3D. All models will incorporate the following features:

Foundations elements will be accounted for by a series of pinned supports at shear walls, foundation walls and columns, where occur.

The foundation walls will be modeled with linear elastic shell elements and will be modeled considering the effects of cracked sections. The effective stiffness will be based on ASCE 41 as described in Table 5 on the following page.

P-delta effects will be included explicitly in the model.

2.2.2 Linear Dynamic Analysis The linear dynamic analysis of the seismic force resisting system will be used to perform parametric studies on items, such as, elastic torsion response, the building’s sensitivity to accidental torsion, and the building’s response to wind forces. The seismic hazard shaking level used for the LDP analysis will be the BSE-1E and the BSE-2E.

The superstructure will be analyzed using a three-dimensional linear response spectrum analysis. This analysis model will be used to check the nonlinear dynamic model and to run parametric studies to confirm effects such as accidental eccentricity and the stiff at grade diaphragm are not significant.

The exterior gravity columns and beams will be modeled as elastic frame elements considered the effects of cracked sections. The effective stiffness will be based on ASCE 41 as described in Table 5 on the following page. The interior gravity frame elements will not be modeled.



The concrete floor diaphragms will be considered semi-rigid (ASCE 41, §7.2.9.1) and modeled using shell elements with effective stiffness based on ASCE 41 per Table 5 below.

Lateral soils springs acting against the out-of-plane direction of the basement walls will not be modeled.

Mass will be uniformly distributed over the floor plate except for walls.

For wall elements mass will be program calculated from the self-weight of the material.

A minimum accidental mass eccentricity of 5% will be considered in the linear model.

A site-specific, 5% damped response spectrum analysis will be used.

Member strength capacities and acceptance criteria will be evaluated in the nonlinear model.

Table 5: Component Stiffness Properties Component Flexural Rigidity

(in-plane) Flexural Rigidity

(out-of-plane) Shear Rigidity Axial Rigidity

Shear Walls 0.35EcIg 0.5EcIg 0.4EcAw 0.5EcAg

Coupling Beams 0.3EcIg 0.5EcIg 0.4EcAg 1.0EcAg

Foundation Walls 0.35EcIg 0.5EcIg 0.4EcAg 1.0EcAg

Concrete Slabs 0.5EcIg 0.5EcIg 0.4EcAg 1.0EcAg

Concrete Columns 0.7EcIg 0.7EcIg 0.4EcAg 1.0EcAg

Concrete Beams 0.3EcIg 0.3EcIg 0.4EcAg 1.0EcAg

2.2.3 Nonlinear Response History Model The Nonlinear Design Model will be used to analyze the response of the Seismic Force Resisting system including the contribution to strength and stiffness from the gravity framing. The features of the Nonlinear Design Model, in addition to the features listed in §2.2.1 above, include:

1. Reinforced concrete walls will be modeled with distributed fiber elements per ASCE 41 using Perform3D General Wall components. See Table 6 below for the cracked stiffness properties, following the recommendations of ASCE 41.



2. Gravity framing will be modeled. Column elements will be modeled as lumped plasticity elements including one elastic element, two moment-rotation hinges at each end to account for joint rotation and bar slip and one shear-displacement hinge mid-span. See Table 6 below for the cracked stiffness properties used for the elastic sections, following the recommendations of ASCE 41.

Gravity beam elements will be modeled elastically with rigid end offsets and considered force-controlled due to the strong-beam weak-column behavior.

3. Concrete slab diaphragms at each floor will be considered rigid. 4. At level 3 through level 9 the mass is applied at a single node at the center-of-mass

location determined using the elastic model. Three mass terms, two horizontal and one rotational are used to account for the spatial distribution of mass.

5. At level 10, roof and penthouse roof, the mass is lumped at two nodes, one centered at the north core and one centered at the south core based on the center of mass location tributary to each core, respectively. Three mass terms are used, two horizontal and one rotational.

6. At level 1 and ground, the mass is distributed over the floor plan. Two horizontal mass terms are used.

7. Using tributary area dead and live loads will be applied to each column at each level. Live loads are applied as unreduced per ASCE 41.

8. Damping: 2.5% modal damping and 0.4% Rayleigh damping will be used for a total of 2.9% viscous damping based on the system and structural height of 150 feet meeting the recommendations of ASCE 41-17 section 7.2.3.6.

9. Duration – Each response history analysis record is adjusted to remove a small portion of the time prior to the strong motion and after the structure comes to rest. This method will decrease computational time and remove unwanted data while preserving the accuracy of the model.

Table 6: Component Stiffness Properties Component Flexural Rigidity

(in-plane) Flexural Rigidity

(out-of-plane) Shear Rigidity Axial Rigidity

Shear Walls 0.35EcIg(1) 0.25EcIg 0.2EcAg 1.0EcAg

Coupling Beams 0.15EcIg 0.25EcIg 0.4EcAg 1.0EcAg

Foundation Walls 0.8EcIg 0.25EcIg 0.2EcAg 1.0EcAg

Diaphragms 1.0 EcIg 0.25EcIg 0.25EcAg 1.0EcAg (1) Effective cracked properties are not used where walls are modeled using fiber elements since the effect of cracked

concrete is automatically accounted for within in the model.



2.2.4 BSE-2E Analysis 1. The Nonlinear Design Model will be used in conjunction with the BSE-2E ground

motions to: a. Establish maximum interstory drifts. b. Monitor residual drift at the end of each record. c. Establish maximum tension and compression strains. d. Establish maximum exterior spandrel beam-to-column connection inelastic

rotation (chord angle) demands. e. Establish design member forces in force-controlled components is less than

calculated capacity. 2. Mass Eccentricity – The effects of accidental torsion will be accounted for where the

elastic model indicates a torsional irregularity occurs. 3. A suite of 11 ground motions’ acceleration history horizontal pairs will be run through

the analysis model. 4. One unacceptable response, as defined below, will be permitted.

a. Analytical solution fails to converge, b. Predicted demands on deformation-controlled elements exceed the valid range of

modeling, c. Predicted demands on critical force-controlled elements, as defined in below

exceed the element capacity, or d. Predicted deformation demands on elements not explicitly modeled exceed the

deformation limit at which the members are no longer able to carry their gravity load.

5. The BSE-2E response values for deformation-controlled elements will be taken as the average of the maximum individual values from load cases at the BSE-2E level and checked against limits in Table 8.

6. The BSE-2E response values for force-controlled elements will be taken as a factor times the mean response. The factor will be as defined in the ASCE 41 provisions to account for the consequence of the loss of a force-controlled element. The equation to calculate force-controlled forces will be:



where Qq is the gravity load; Quf is average of the maximum value the force controlled action’s force in a component from each of the ground motion suites; Qcl is the lower-bound component strength; and is the load factor obtained from Table 7. is the performance level factor, equal to 1.0 for Collapse Prevention. Where an industry standard defines lower-bound strength, that value will be used. Where this is not defined, it will be permitted to calculate lower-bound strength as the nominal strength defined in industry standards using nominal material properties per ASCE 41 in lieu of specified values. Strength reduction factor will be taken as unity.

7. Critical force-controlled elements will also be evaluated for the maximum BSE-2E force from all the records against their expected capacity.

Table 7: Load Factor for Critical and Ordinary Force-Controlled Behaviors Action Type Load Factor, Critical Column axial force

Column shear force Beam shear force Total wall shear force Shear wall axial compression Coupling beam shear force Diaphragm shear force at transfers

1.3

Ordinary Foundation wall shear Foundation wall flexure Individual wall shear

1.0

Noncritical Diaphragm Shear when not explicitly modeled 1.0



Table 8: Collapse Prevention Acceptance Criteria for Components

Component Classification Acceptance Criteria

Shear wall Reinforcement Strains

Deformation-Controlled

0.05 in/in (tension), 0.02 in/in (compression)

Shear wall Concrete Compressive Strains (unconfined)


0.002 in/in

Shear wall Concrete Compressive Strains (Confined)


0.01 in/in

Shear Wall Plastic Hinge Rotation (flexural controlled)


Unconfined Boundary Axial Load <0.1 V<4(f’c)1/2 0.015 radians V>6(f’c)1/2 0.010 radians Axial Load >0.25 V<4(f’c)1/2 0.005 radians V>6(f’c)1/2 0.004 radians

Coupling Beam Rotation (shear controlled)


≤3 0.02 ≥6 0.012

Coupling Beam Rotation (flexural controlled)


≤3 0.035 ≥6 0.025

Column Hinge Rotation Deformation-Controlled

Per ASCE 41 Table 10-8

2.2.5 BSE-1E Analysis 1. The Nonlinear Design Model will be used in conjunction with the BSE-1E ground

motions to: a. Establish maximum interstory drifts. b. Monitor residual drift at the end of each record. c. Establish maximum tension and compression strains. d. Establish maximum exterior spandrel beam-to-column connection inelastic

rotation (chord angle) demands. e. Establish design member forces in force-controlled components including the

shear demand in the shear walls and coupling beam elements.



2. Mass Eccentricity – The effects of accidental torsion will be accounted for where the elastic model indicates a torsional irregularity occurs.

3. A suite of 11 ground motions’ acceleration history horizontal pairs will be run through the analysis model.

4. One unacceptable response, as defined below, will be permitted in the final retrofit. a. Analytical solution fails to converge, b. Predicted demands on deformation-controlled elements exceed the valid range of

modeling, c. Predicted demands on critical force-controlled elements, as defined in below

exceed the element capacity, or d. Predicted deformation demands on elements not explicitly modeled exceed the

deformation limit at which the members are no longer able to carry their gravity load.

5. The BSE-1E response values for deformation-controlled elements will be taken as the average of the maximum individual values from load cases at the BSE-1E level and checked against limits in Table 9.

6. The BSE-1E response values for force-controlled elements will be taken as a factor times the mean response. The factor will be as defined in the ASCE 41 provisions to account for the consequence of the loss of a force-controlled element. The equation to calculation force-controlled forces will be:

where Qq is the gravity load; Quf is average of the maximum value the force controlled action’s force in a component from each of the 11 ground motion records; Qcl is the lower-bound component strength; and is the load factor obtained from Table 7. is the performance level factor, equal to 1.3 for Life Safety. Where an industry standard defines lower-bound strength, that value will be used. Where this is not defined, it will be permitted to calculate lower-bound strength as the nominal strength defined in industry standards using nominal material properties per ASCE 41 in lieu of specified values. Strength reduction factor will be taken as unity.

7. Critical force-controlled elements will also be evaluated for the maximum BSE-1E force from all the records against their expected capacity.



Table 9: Life Safety Acceptance Criteria for Components

Component Classification Acceptance Criteria

Shear Wall Reinforcement Strains


0.05 in/in (tension), 0.02 in/in (compression)

Shear Wall Compressive Strains (unconfined)


0.002 in/in

Shear wall Concrete Compressive Strains (confined)


0.008 in/in

Shear Wall Plastic Hinge Rotation


Unconfined Boundary Axial Load <0.1 V<4(f’c)1/2 0.008 radians V>6(f’c)1/2 0.006 radians Axial Load >0.25 V<4(f’c)1/2 0.003 radians V>6(f’c)1/2 0.002 radians

Coupling Beam Rotation (shear controlled)


≤3 0.01 ≥6 0.007

Coupling Beam Rotation (flexural controlled)


≤3 0.02 ≥6 0.01

Column Hinge Rotation Deformation-Controlled

Per ASCE 41 Table 10-8

Date post:	12-Jul-2020
Category:	Documents
Upload:	others
View:	2 times
Download:	0 times