350-01/350R-01 CODE REQUIREMENTS FOR ENVIRONMENTAL ...civilwares.free.fr/ACI/MCP04/350_01.pdf ·...

ACI 350 Environmental Structures Code and Commentary

Charles S. HanskatChairman

Lawrence M. TabatSecretary

James P. Archibald* A. Ray Frankson M. Reza Kianoush David M. Rogowsky

Jon B. Ardahl Anand B. Gogate David G. Kittridge Satish K. SachdevWalter N. Bennett William J. Hendrickson Nicholas A. Legatos William C. SchnobrichSteven R. Close Jerry A. Holland Larry G. Mrazek Sudhaker P. VermaAshok K. Dhingra William Irwin Jerry Parnes Roger H. WoodAnthony L. Felder Dov Kaminetzky Andrew R. M. Philip

Voting Subcommittee Members

Osama Abdel-Aai Clifford T. Early Jack Moll William C. ShermanJohn Baker Clifford Gordon Carl H. Moon Lauren A. SusticPatrick J. Creegan Paul Hedli Javeed A. Munshi Lawrence J. ValentineDavid A. Crocker Keith W. Jacobson Terry Patzias Miroslav VejvodaErnst T. Cvikl Dennis C. Kohl Narayan M. Prachand Paul ZoltanetzkyRobert E. Doyle Bryant Mather John F. Seidensticker

*Past-Secretary of ACI 350 who served during a portion of the time required to create this document.Past-Chairman of ACI 350 who served during a portion of the time required to create this document.

CODE REQUIREMENTS FORENVIRONMENTAL ENGINEERING

CONCRETE STRUCTURES (ACI 350-01)AND COMMENTARY (ACI 350R-01)

REPORTED BY ACI COMMITTEE 350

ACI Committee 350Environmental Engineering Concrete Structures


318/318R-2 CHAPTER 1

INTRODUCTION 350/350R-1

The code portion of this document covers the structural design, materials selection, and construction ofenvironmental engineering concrete structures. Such structures are used for conveying, storing, or treatingliquid, wastewater, or other materials, such as solid waste. They include ancillary structures for dams, spill-ways, and channels.

They are subject to uniquely different loadings, more severe exposure conditions and more restrictiveserviceability requirements than normal building structures.

Loadings include normal dead and live loads and vibrating equipment or hydrodynamic forces. Expo-sures include concentrated chemicals, alternate wetting and drying, and freezing and thawing of saturatedconcrete. Serviceability requirements include liquid-tightness or gas-tightness.

Typical structures include conveyance, storage, and treatment structures.

Proper design, materials, and construction of environmental engineering concrete structures are re-quired to produce serviceable concrete that is dense, durable, nearly impermeable, resistant to chemicals,with limited deflections and cracking. Leakage must be controlled to minimize contamination of ground wa-ter or the environment, to minimize loss of product or infiltration, and to promote durability.

This code presents new material as well as modified portions of the ACI 318-95 Building Code that areapplicable to environmental engineering concrete structures.

Because ACI 350-01 is written as a legal document, it may be adopted by reference in a general buildingcode or in regulations governing the design and construction of environmental engineering concrete struc-tures. Thus it cannot present background details or suggestions for carrying out its requirements or intent.It is the function of the commentary to fill this need.

CODE REQUIREMENTS FOR ENVIRONMENTAL ENGINEERING CONCRETE STRUCTURES(ACI 350-01) AND COMMENTARY (ACI 350R-01)

REPORTED BY ACI COMMITTEE 350

ACI 350/350R-01 was adopted as a standard of the American ConcreteInstitute on December 11, 2001 in accordance with the Institutes standard-ization procedure.

Text marks in the margins indicate the code and commentary changesfrom 318/318R-95.

ACI Committee Reports, Guides, Standard Practices, and Commentariesare intended for guidance in planning, designing, executing, and inspectingconstruction. This Commentary is intended for the use of individuals whoare competent to evaluate the significance and limitations of its content andrecommendations and who will accept responsibility for the application ofthe material it contains. The American Concrete Institute disclaims any andall responsibility for the stated principles. The Institute shall not be liable for

any loss or damage arising therefrom. Reference to this commentary shall notbe made in contract documents. If items found in this Commentary are de-sired by the Architect/Engineer to be a part of the contract documents, theyshall be restated in mandatory language for incorporation by the Architect/Engineer.

Copyright 2001, American Concrete Institute.All rights reserved including rights of reproduction and use in any form

or by any means, including the making of copies by any photo process, orby any electronic or mechanical device, printed or written or oral, or record-ing for sound or visual reproduction or for use in any knowledge or retrievalsystem or device, unless permission in writing is obtained from the copy-right proprietors.

ACI 350 Environmental Structures Code and Commentary350/350R-1

350/350R-2 INTRODUCTION

The commentary discusses some of the considerations of the committee in developing the ACI 350 Code,and its relationship with ACI 318. Emphasis is given to the explanation of provisions that may be unfamiliarto some code users. References to much of the research data referred to in preparing the code are givenfor those who wish to study certain requirements in greater detail.

The chapter and section numbering of the code are followed throughout the commentary.Among the subjects covered are: permits, drawings and specifications, inspections, materials, concrete

quality, mixing and placing, forming, embedded pipes, construction joints, reinforcement details, analysisand design, strength and serviceability, flexural and axial loads, shear and torsion, development of rein-forcement, slab systems, walls, footings, precast concrete, prestressed concrete, shell structures, foldedplate members, provisions for seismic design, and an alternate design method in Appendix A.

The quality and testing of materials used in the construction are covered by reference to the appropriatestandard specifications. Welding of reinforcement is covered by reference to the appropriate AWS stan-dard. Criteria for liquid-tightness testing may be found in 350.1 and 350.1R.

Keywords: Chemical attack; coatings; concrete durability; concrete finishing (fresh concrete); concrete slabs, crack width, and spacing; cracking(fracturing); environmental engineering; inspection; joints (junctions); joint sealers; liquid; patching; permeability; pipe columns; pipes (tubes);prestressed concrete; prestressing steels; protective coatings; reservoirs; roofs; environmental engineering; serviceability; sewerage; solid wastefacilities; tanks (containers); temperature; torque; torsion; vibration; volume change; walls; wastewater treatment; water; water-cement ratio; wa-ter supply; water treatment.

The 2001 Code Requirements for Environmental Engineering Concrete Structures and Commentary are present-ed in a side-by-side column format, with code text placed in the left column and the corresponding commentarytext aligned in the right column. To further distinguish the Code from the Commentary, the Code has been printedin Helvetica, the same type face in which this paragraph is set. Text marks in the margins indicate paragraphswith changes from ACI 318-95.

This paragraph is set in Times Roman, and all portions of the text exclusive to the Commentary are printed in this type face.Commentary section numbers are preceded by an R to further distinguish them from Code section numbers. Text marksin the margins indicate paragraphs with changes from ACI 318-95.

INTRODUCTION

The code and commentary includes excerpts from ACI 318-95that are pertinent to ACI 350. The commentary discusses someof the considerations of Committee ACI 350 in developingCode Requirements for Environmental Engineering ConcreteStructures (ACI 350-01), hereinafter called the code. Emphasisis given to the explanation of provisions that may be unfamiliarto ACI 350 users. Comments on specific provisions are madeunder the corresponding chapter and section numbers of thecode and commentary.

This commentary is not intended to provide a complete histor-ical background concerning the development of the code, noris it intended to provide a detailed resume of the studies and re-search data reviewed by the committee in formulating the pro-visions of the code. However, references to some of theresearch data are provided for those who wish to study thebackground material in depth.

As the name implies, Code Requirements for Environmen-tal Engineering Concrete Structures is meant to be used aspart of a legally adopted code and, as such, must differ inform and substance from documents that provide detailedspecifications, recommended practice, complete design pro-cedures, or design aids.

The code is intended to cover environmental engineering con-crete structures of the usual types, both large and small, but is notintended to supersede ASTM standards for precast structures.

ACI 350 Environmental Stru

Requirements more stringent than the code provisions may bedesirable for unusual structures. This code and this commen-tary cannot replace sound engineering knowledge, experience,and judgment.

A code for design and construction states the minimum re-quirements necessary to provide for public health and safety.ACI 350 is based on this principle. For any structure theowner or the structural designer may require the quality ofmaterials and construction to be higher than the minimum re-quirements necessary to provide serviceability and to protectthe public as stated in the code. Lower standards, however,are not permitted.

ACI 350 has no legal status unless it is adopted by governmentbodies having the power to regulate building design and con-struction. Where the code has not been adopted, it may serve asa reference to good practice.

The code provides a means of establishing minimum standardsfor acceptance of design and construction by a legally appoint-ed building official or his designated representatives. The codeand commentary are not intended for use in settling disputesbetween the owner, engineer, architect, contractor, or theiragents, subcontractors, material Suppliers, or testing agencies.Therefore, the code cannot define the contract responsibility ofeach of the parties in usual construction. General references re-quiring compliance with ACI 350 in the job specificationsshould be avoided, since the contractor is rarely in a position toaccept responsibility for design details or construction

ctures Code and Commentary

INTRODUCTION 350/350R-3

requirements that depend on a detailed knowledge of the de-sign. Generally, the drawings, specifications, and contract doc-uments should contain all of the necessary requirements toensure compliance with the code. In part, this can be accom-plished by reference to specific code sections in the job speci-fications. Other ACI publications, such as ACI 301,Specifications for Structural Concrete are written specifical-ly for use as contract documents for construction.

Committee 350 recognizes the desirability of standards of per-formance for individual parties involved in the contract docu-ments. Available for this purpose are the certification programsof the American Concrete Institute, the plant certification pro-grams of the Precast/Prestressed Concrete Institute, the Nation-al Ready Mixed Concrete Association, and the qualificationstandards of the American Society of Concrete Constructors.Also available are Standard Specification for Agencies En-gaged in the Testing and/or Inspection of Materials Used inConstruction (ASTM E 329) and Standard Practice for Lab-oratories Testing Concrete and Concrete Aggregates for Use inConstruction and Criteria for Laboratory Evaluation (ASTMC 1077).

Design aids (general concrete design aids are listed in318-95):

Rectangular Concrete Tanks, Portland Cement Associa-tion, Skokie, IL, 1994, 176 pp. (Presents data for design of rect-angular tanks.)

Circular Concrete Tanks Without Prestressing, PortlandCement Association, Skokie, IL, 1993, 54 pp. (Presents designdata for circular concrete tanks built in or on ground. Wallsmay be free or restrained at the top. Wall bases may be fixed,hinged, or have intermediate degrees of restraint. Various lay-outs for circular roofs are presented.)

Concrete Manual, U.S. Department of Interior, Bureau ofReclamation, 8th edition, 1981, 627 pp. (Presents technical in-formation for the control of concrete construction, includinglinings for tunnels, impoundments, and canals.)

GENERAL COMMENTARY

Because of stringent service requirements, environmental en-gineering concrete structures should be designed and detailedwith care. The quality of concrete is important, and close qual-ity control must be performed during construction to obtain im-pervious concrete with smooth surfaces.

Environmental engineering concrete structures for the contain-ment, treatment, or transmission of liquid, wastewater, or otherfluids, as well as solid waste disposal facilities, should be de-signed and constructed to be essentially liquid-tight, with min-imal leakage under normal service conditions.

The liquid-tightness of a structure will be reasonably assured if:

ACI 350 Environmental Structures

a) The concrete mixture is well proportioned, well consol-idated without segregation, and properly cured.

b) Crack widths and depths are minimized.c) Joints are properly spaced, sized, designed, water-

stopped, and constructed.d) Adequate reinforcing steel is provided, properly de-

tailed, fabricated, and placed.e) Impervious protective coatings or barriers are used

where required.

Usually it is more economical and dependable to resist liquidpermeation through the use of quality concrete, proper designof joint details, and adequate reinforcement, rather than bymeans of an impervious protective barrier or coating. Liquid-tightness can also be obtained by appropriate use of shrinkage-compensating concrete. However, to achieve success, the engi-neer must recognize and account for the limitations, character-istics, and properties of shrinkage-compensating concrete asdescribed in ACI 223 and ACI 224.2R.

Minimum permeability of the concrete will be obtained by us-ing water-cementitious materials ratios as low as possible, con-sistent with satisfactory workability and consolidation.Impermeability increases with the age of the concrete and isimproved by extended periods of moist curing. Surface treat-ment is important and use of smooth forms or troweling im-proves impermeability. Air entrainment reduces segregationand bleeding, increases workability, and provides resistance tothe effect of freeze-thaw cycles. Because of this, use of an air-entraining admixture results in better consolidated concrete.Other admixtures, such as water-reducing agents and poz-zolans are useful when they lead to increased workability andconsolidation, and lower water-cementitious ratios. Pozzolansalso reduce permeability.

Joint design should also account for movement resulting fromthermal dimensional changes and differential settlements.Joints permitting movement along predetermined controlplanes, and which form a barrier to the passage of fluids, shallinclude waterstops in complete, closed circuits. Proper rate ofplacement operations, adequate consolidation, and proper cur-ing are also essential to control of cracking in environmentalengineering concrete structures. Additional information oncracking is contained in ACI 224R and ACI 224.2R.

The design of the whole environmental engineering concretestructure as well as all individual members should be inaccordance with ACI 350-01, which has been adapted fromACI 318-95. When all relevant loading conditions are con-sidered, the design should provide adequate safety and ser-viceability, with a life expectancy of 50 to 60 years for thestructural concrete. Some components of the structure, suchas jointing materials, have a shorter life expectancy and willrequire maintenance or replacement.

The size of elements and amount of reinforcement should beselected on the basis of the serviceability crack-width limitsand stress limits to promote long service life.

Code and Commentary

350/350R-4 TABLE OF CONTENTS

CONTENTS

PART 1GENERAL

CHAPTER 1GENERAL REQUIREMENTS.......................................... 350/350R-9

1.1Scope 1.3Inspection1.2Drawings and specifications 1.4Approval of special systems of design or construction

CHAPTER 2DEFINITIONS ................................................................ 350/350R-17

PART 2STANDARDS FOR TESTS AND MATERIALS

CHAPTER 3MATERIALS .................................................................. 350/350R-25

3.0Notation 3.5Steel reinforcement3.1Tests of materials 3.6Admixtures3.2Cements 3.7Storage of materials3.3Aggregates 3.8Standards cited in this code3.4Water

PART 3CONSTRUCTION REQUIREMENTS

CHAPTER 4DURABILITY REQUIREMENTS ................................... 350/350R-39

4.0Notation 4.5Chemical effects4.1Water-cementitious materials ratio 4.6Protection against erosion4.2Freezing and thawing exposures 4.7Coatings and liners4.3Sulfate exposures 4.8Joints4.4Corrosion protection of metals

CHAPTER 5CONCRETE QUALITY, MIXING, AND PLACING ........ 350/350R-51

5.0Notation 5.7Preparation of equipment and place of deposit5.1General 5.8Mixing5.2Selection of concrete proportions 5.9Conveying5.3Proportioning on the basis of field experience 5.10Depositing

and/or trial mixtures 5.11Curing5.4Not used 5.12Cold weather requirements5.5Average strength reduction 5.13Hot weather requirements5.6Evaluation and acceptance of concrete

CHAPTER 6FORMWORK, EMBEDDED PIPES, AND CONSTRUCTIONAND MOVEMENT JOINTS ............................................ 350/350R-67

6.1Design of formwork 6.4Construction joints6.2Removal of forms, shores, and reshoring 6.5Movement joints6.3Conduits and pipes embedded in concrete

CHAPTER 7DETAILS OF REINFORCEMENT ................................. 350/350R-73

7.0Notation 7.7Concrete protection for reinforcement7.1Standard hooks 7.8Special reinforcement details for columns7.2Minimum bend diameters 7.9Connections7.3Bending 7.10Lateral reinforcement for compression members7.4Surface conditions of reinforcement 7.11Lateral reinforcement for flexural members7.5Placing reinforcement 7.12Shrinkage and temperature reinforcement7.6Spacing limits for reinforcement 7.13Requirements for structural integrity


TABLE OF CONTENTS 350/350R-5

PART 4GENERAL REQUIREMENTS

CHAPTER 8ANALYSIS AND DESIGNGENERALCONSIDERATIONS...........................................................350/350R-87

8.0Notation 8.6Stiffness8.1Design methods 8.7Span length8.2Loading 8.8Columns8.3Methods of analysis 8.9Arrangement of live load8.4Redistribution of negative moments in continuous 8.10T-beam construction

nonprestressed flexural members 8.11Joist construction8.5Modulus of elasticity 8.12Separate floor finish

CHAPTER 9STRENGTH AND SERVICEABILITYREQUIREMENTS ..............................................................350/350R-97

9.0Notation 9.3Design strength9.1General 9.4Design strength for reinforcement9.2Required strength 9.5Control of deflections

CHAPTER 10FLEXURE AND AXIAL LOADS ....................................350/350R-111

10.0Notation 10.8Design dimensions for compression members10.1Scope 10.9Limits for reinforcement of compression members10.2Design assumptions 10.10Slenderness effects in compression members10.3General principles and requirements 10.11Magnified momentsGeneral10.4Distance between lateral supports of 10.12Magnified momentsNon-sway frames

flexural members 10.13Magnified momentsSway frames10.5Minimum reinforcement of flexural members 10.14Axially loaded members supporting slab system10.6Distribution of flexural reinforcement in beams and 10.15Transmission of column loads through floor system

one-way slabs 10.16Composite compression members10.7Deep flexural members 10.17Bearing strength

CHAPTER 11SHEAR AND TORSION ................................................350/350R-141

11.0Notation 11.6Design for torsion11.1Shear strength 11.7Shear-friction11.2Lightweight concrete 11.8Special provisions for deep flexural members11.3Shear strength provided by concrete for 11.9Special provisions for brackets and corbels

nonprestressed members 11.10Special provisions for walls11.4Shear strength provided by concrete for 11.11Transfer of moments to columns

prestressed members 11.12Special provisions for slabs and footings11.5Shear strength provided by shear reinforcement

CHAPTER 12DEVELOPMENT AND SPLICES OFREINFORCEMENT .......................................................350/350R-187

12.0Notation 12.10Development of flexural reinforcementGeneral12.1Development of reinforcementGeneral 12.11Development of positive moment reinforcement12.2Development of deformed bars and deformed 12.12Development of negative moment reinforcement

wire in tension 12.13Development of web reinforcement12.3Development of deformed bars in compression 12.14Splices of reinforcementGeneral12.4Development of bundled bars 12.15Splices of deformed bars and deformed wire in12.5Development of standard hooks in tension tension12.6Mechanical anchorage 12.16Splices of deformed bars in compression12.7Development of welded deformed wire fabric in 12.17Special splice requirements for columns

tension 12.18Splices of welded deformed wire fabric in tension12.8Development of welded plain wire fabric in tension 12.19Splices of welded plain wire fabric in tension12.9Development of prestressing strand



PART 5STRUCTURAL SYSTEMS OR ELEMENTS

CHAPTER 13TWO-WAY SLAB SYSTEMS .................................... 350/350R-215

13.0Notation 13.4Openings in slab systems13.1Scope 13.5Design procedures13.2Definitions 13.6Direct design method13.3Slab reinforcement 13.7Equivalent frame method

CHAPTER 14WALLS ...................................................................... 350/350R-235

14.0Notation 14.4Walls designed as compression members14.1Scope 14.5Empirical design method14.2General 14.6Minimum wall thickness14.3Minimum reinforcement 14.7Walls as grade beams

CHAPTER 15FOOTINGS ................................................................ 350/350R-239

15.0Notation 15.6Development of reinforcement in footings15.1Scope 15.7Minimum footing depth15.2Loads and reactions 15.8Transfer of force at base of column, wall,15.3Footings supporting circular or regular polygon or reinforced pedestal

shaped columns or pedestals 15.9Sloped or stepped footings15.4Moment in footings 15.10Combined footings and mats15.5Shear in footings

CHAPTER 16PRECAST CONCRETE............................................. 350/350R-245

16.0Notation 16.6Connection and bearing design16.1Scope 16.7Items embedded after concrete placement16.2General 16.8Marking and identification16.3Distribution of forces among members 16.9Handling16.4Member design 16.10Strength evaluation of precast construction16.5Structural integrity

CHAPTER 17COMPOSITE CONCRETE FLEXURALMEMBERS ................................................................. 350/350R-253

17.0Notation 17.4Vertical shear strength17.1Scope 17.5Horizontal shear strength17.2General 17.6Ties for horizontal shear17.3Shoring

CHAPTER 18PRESTRESSED CONCRETE ................................... 350/350R-257

18.0Notation 18.11Compression membersCombined flexure and18.1Scope axial loads18.2General 18.12Slab systems18.3Design assumptions 18.13Tendon anchorage zones18.4Permissible stresses in concreteFlexural members 18.14Corrosion protection for unbonded prestressing18.5Permissible stresses in prestressing tendons tendons18.6Loss of prestress 18.15Post-tensioning ducts18.7Flexural strength 18.16Grout for bonded prestressing tendons18.8Limits for reinforcement of flexural members 18.17Protection for prestressing tendons18.9Minimum bonded reinforcement 18.18Application and measurement of prestressing force18.10Statically indeterminate structures 18.19Post-tensioning anchorages and couplers


TABLE OF CONTENTS 350/350R-7

CHAPTER 19SHELLS AND FOLDED PLATE MEMBERS ................350/350R-279

19.0Notation 19.3Design strength of materials19.1Scope and definitions 19.4Shell reinforcement19.2Analysis and design 19.5Construction

PART 6SPECIAL CONSIDERATIONS

CHAPTER 20STRENGTH EVALUATION OF EXISTINGSTRUCTURES ..............................................................350/350R-287

20.0Notation 20.4Loading criteria20.1Strength evaluationGeneral 20.5Acceptance criteria20.2Determination of required dimensions and material 20.6Provision for lower load rating

properties 20.7Safety20.3Load test procedure

CHAPTER 21SPECIAL PROVISIONS FOR SEISMIC DESIGN .........350/350R-293

21.0Notation 21.5Joints of frames21.1Definitions 21.6Structural walls, diaphragms, and trusses21.2General requirements 21.7Frame members not proportioned to resist forces21.3Flexural members of frames induced by earthquake motions21.4Frame members subjected to bending and 21.8Requirements for frames in regions of moderate

axial load seismic risk

PART 7STRUCTURAL PLAIN CONCRETE

CHAPTER 22STRUCTURAL PLAIN CONCRETE..............................350/350R-323

COMMENTARY REFERENCES.....................................................350/350R-325

APPENDICES

APPENDIX AALTERNATE DESIGN METHOD ..................................350/350R-337

A.0Notation A.4Development and splices of reinforcementA.1Scope A.5FlexureA.2General A.6Compression members with or without flexureA.3Permissible service load stresses A.7Shear and torsion

APPENDIX BNOT USED.....................................................................350/350R-351

APPENDIX CNOT USED.....................................................................350/350R-353

APPENDIX DNOTATION.....................................................................350/350R-355

APPENDIX EMETAL REINFORCEMENT INFORMATION.................350/350R-361



APPENDIX FCIRCULAR WIRE AND STRAND WRAPPEDPRESTRESSED CONCRETE ENVIRONMENTALSTRUCTURES ........................................................... 350/350R-363

F.0Notation F.3MaterialsF.1Scope F.4Construction proceduresF.2Design

APPENDIX GSLABS ON SOIL ....................................................... 350/350R-379

G.1Scope G.5JointsG.2Subgrade G.6Hydrostatic upliftG.3Slab thickness G.7CuringG.4Reinforcement

INDEX .................................................................................................. 350/350R-383


CHAPTER 1 350/350R-9

PART 1 GENERAL

CODE1.1 Scope

ACI 350 Environmental

COMMENTARY

R1.1 Scope

The American Concrete Institute Code Requirements forEnvironmental Engineering Concrete Structures (ACI 350-01), hereinafter referred to as the code, provide minimumrequirements for environmental engineering concrete struc-tural design and construction practices.

Prestressed concrete is included under the definition of rein-forced concrete. Provisions of ACI 350-01 apply to pre-stressed concrete except in cases in which the provisions ofthe code are stated to apply specifically to nonprestressedconcrete.

Appendix A of ACI 350 contains provisions for the Alter-nate Design Method for nonprestressed reinforced concretemembers using service loads (without load factors) and per-missible service-load stresses. The Strength Design Methodof this code is intended to give design results similar to theAlternate Design Method.

1.1.1 Except for primary containment of hazardousmaterials, this code provides minimum requirementsfor the design and construction of reinforced concretestructural elements of any environmental engineeringconcrete structure, erected under the requirements ofthe legally adopted building code of which this codeforms a part. In areas without a legally adopted build-ing code, this code defines minimum acceptable stan-dards of design and construction practice.

Stru

R1.1.1 A hazardous material is defined as having one ormore of the following characteristics: ignitable (NFPA 49),corrosive, reactive, or toxic. EPA listed wastes are organizedinto three categories under RCRA: source specific wastes,generic wastes, and commercial chemical products. Sourcespecific wastes include sludges and wastewaters from treat-ment and production processes in specific industries such aspetroleum refining and wood preserving. The list of genericwastes includes wastes from common manufacturing andindustrial processes such as solvents used in de-greasingoperations. The third list contains specific chemical productssuch as benzine, creosote, mercury, and various pesticides.

1.1.1.1 Environmental engineering concretestructures are defined as concrete structures intendedfor conveying, storing, or treating water, wastewater, orother non-hazardous liquids, and for secondary con-tainment of hazardous liquids. Other than circulartanks, precast environmental structures designed andconstructed in accordance with ASTM or AWWA arenot covered in this code.

1.1.2 This code supplements the general buildingcode and shall govern in all matters pertaining todesign and construction of reinforced concrete struc-tural elements of any environmental engineering con-crete structure, except wherever this code is in conflictwith requirements in the legally adopted general build-ing code.

c

R1.1.2 The American Concrete Institute recommendsthat the code be adopted in its entirety; however, it is recog-nized that when the code is made a part of a legally adoptedgeneral building code, that general building code may mod-ify some provisions of this code.

CHAPTER 1 GENERAL REQUIREMENTS

tures Code and Commentary

350/350R-10 CHAPTER 1

CODE COMMENTARY
1.1.3 This code shall govern in all matters pertain-ing to design, construction, and material propertieswherever this code is in conflict with requirements con-tained in other standards referenced in this code.
1.1.4 The provisions of this code shall govern fortanks, reservoirs, and other reinforced concrete ele-ments of any environmental engineering concretestructure.

ACI 350 Environmental Struc

R1.1.4 Environmental engineering projects can containseveral types of special structures. For example, a treatmentplant can contain environmental structures such as tanks andreservoirs, as well as silos and buildings. The ACI 350-01code would apply to the environmental structures, while theACI 318 code or the following ACI publications couldapply to the other special structures.

Standard Practice for the Design and Construction ofCast-in-Place Reinforced Concrete Chimneys reported

by ACI Committee 307.1.1 (Gives material, construction,and design requirements for circular cast-in-place rein-forced chimneys. It sets forth minimum loadings for thedesign of reinforced concrete chimneys and contains meth-ods for determining the stresses in the concrete and rein-forcement required as a result of these loadings.)

Standard Practice for Design and Construction of Con-crete Silos and Stacking Tubes for Storing Granular

Materials reported by ACI Committee 313.1.2 (Givesmaterial, design, and construction requirements for reinforcedconcrete bins, silos, and bunkers and stave silos for storinggranular materials. It includes recommended design and con-struction criteria based on experimental and analytical studiesplus worldwide experience in silo design and construction.)

(Bins, silos, and bunkers are special structures, posing spe-cial problems not encountered in normal building design.While this standard practice refers to Building CodeRequirements for Structural Concrete (ACI 318) formany applicable requirements, it provides supplementaldetail requirements and ways of considering the uniqueproblems of static and dynamic loading of silo structures.Much of the method is empirical, but this standard practicedoes not preclude the use of more sophisticated methodswhich give equivalent or better safety and reliability.)

(This standard practice sets forth recommended loadingsand methods for determining the stresses in the concrete andreinforcement resulting from these loadings. Methods arerecommended for determining the thermal effects resultingfrom stored material and for determining crack width in con-crete walls due to pressure exerted by the stored material.Appendices provide recommended minimum values ofoverpressure and impact factors.)

Code Requirements for Nuclear Safety Related Con-

crete Structures reported by ACI Committee 349.1.3 (Pro-vides minimum requirements for design and construction ofconcrete structures which form part of a nuclear power plantand which have nuclear safety related functions. The codedoes not cover concrete reactor vessels and concrete con-tainment structures which are covered by ACI 359.)


CHAPTER 1 350/350R-11

CODE


COMMENTARYCode for Concrete Reactor Vessels and Containments

reported by ACI-ASME Committee 359.1.4 (Providesrequirements for the design, construction, and use of con-crete reactor vessels and concrete containment structures fornuclear power plants.)

1.1.5 This code does not govern design and instal-lation of portions of concrete piles and drilled piersembedded in ground.

R1.1.5 The design and installation of piling fully embed-ded in the ground is regulated by the general building code.For portions of piling in air or water, or in soil not capableof providing adequate lateral restraint throughout the pilinglength to prevent buckling, the design provisions of thiscode govern where applicable.

Recommendations for concrete piles are given in detail inRecommendations for Design, Manufacture, andInstallation of Concrete Piles reported by ACI Commit-

tee 543.1.5 (Provides recommendations for the design anduse of most types of concrete piles for many kinds of con-struction.)

Recommendations for drilled piers are given in detail inDesign and Construction of Drilled Piers reported by

ACI Committee 336.1.6 (Provides recommendations fordesign and construction of foundation piers 21/2 ft in diame-ter or larger made by excavating a hole in the soil and thenfilling it with concrete.)

1.1.6 This code governs the design and constructionof soil-supported slabs as required by Appendix G.
Slabs that transmit vertical loads from other portions ofthe structure to the soil shall meet the requirements ofother chapters of this code as applicable.
R1.1.6 Since tank floor slabs frequently directly transfer theloads from liquid contents to the soil below, Appendix G hasbeen added to this code to provide appropriate requirements.

1.1.7 Concrete on steel form deck
R1.1.7 Concrete on steel form deck
In steel framed structures, it is common practice to cast con-crete floor slabs on stay-in-place steel form deck. In allcases, the deck serves as the form and may, in some cases,serve an additional structural function.

1.1.7.1 Design and construction of structuralconcrete slabs cast on stay-in-place, noncompositesteel form deck are governed by this code.

R1.1.7.1 In its most basic application, the steel formdeck serves as a form, and the concrete serves a structuralfunction and, therefore, must be designed to carry all super-imposed loads.

1.1.7.2 This code does not govern the design ofstructural concrete slabs cast on stay-in-place, com-posite steel form deck. Concrete used in the construc-tion of such slabs shall be governed by Parts 1, 2, and3 of this code, where applicable.

R1.1.7.2 Another type of steel form deck commonlyused develops composite action between the concrete andsteel deck. In this type of construction, the steel deck servesas the positive moment reinforcement. The design of compos-ite slabs on steel deck is regulated by Standard for the

Structural Design of Composite Slabs (ANSI/ASCE 3).1.7

However, ANSI/ASCE 3 references the appropriate portionsof ACI 318 for the design and construction of the concreteportion of the composite assembly. Guidelines for the con-struction of composite steel deck slabs are given in Stan-dard Practice for the Construction and Inspection of

Composite Slabs (ANSI/ASCE 9).1.8


350/350R-12 CHAPTER 1

CODE COMMENTARY
1.1.8 Special provisions for earthquake resistance
ACI 350 Environmental Struct

R1.1.8 Special provisions for earthquake resistance

Special provisions for seismic design were first introducedin Appendix A of the 1971 ACI 318 Building Code andwere continued without revision in ACI 318-77. These pro-visions were originally intended to apply only to reinforcedconcrete structures located in regions of highest seismicity.

The special provisions were extensively revised in the 1983code edition to include new requirements for certain earth-quake-resisting systems located in regions of moderate seis-micity. In the 1989 code, the special provisions were movedto Chapter 21.

1.1.8.1 In regions of low seismic risk, provisionsof Chapter 21 shall be satisfied. See 21.2.1.

R1.1.8.1 Some structures and elements of structureswill have their design governed by hydrodynamic forces,even when located in areas of low seismic risk, due to theirconfiguration and position. Portions of Chapter 21 (21.2 and21.6) apply to liquid-containing structures for all levels ofseismic risk.

Aside from provisions given in 21.2 and 21.6, no specialdesign or detailing is required for structures located in regionsof low seismic risk; the general requirements of the main bodyof the code apply for proportioning and detailing reinforcedconcrete structures. It is the intent of Committee 350 that con-crete structures proportioned by the main body of the codewill provide a level of strength and ductility adequate forlow earthquake intensity, provided that provisions given in21.2 and 21.6 are followed.

1.1.8.2 In regions of moderate or high seismicrisk, provisions of Chapter 21 shall be satisfied. See21.2.1.

R1.1.8.2 For structures in regions of moderate seismicrisk, reinforced concrete moment frames proportioned toresist earthquake effects require some special reinforcementdetails, as specified in 21.8 of Chapter 21. The special details
apply only to frames (beams, columns, and slabs) to whichthe earthquake-induced forces have been assigned in design.The special details are intended principally for unbraced con-crete frames, where the frame is required to resist not onlynormal load effects, but also the lateral load effects of earth-quakes. The special reinforcement details will serve to pro-vide a suitable level of inelastic behavior if the frame issubjected to an earthquake of such intensity as to require it toperform inelastically. The load factors required by this codewill limit the extent of inelastic response.
For structures located in regions of high seismic risk, allstructure components, structural and nonstructural, shouldsatisfy requirements of 21.2 through 21.7 of Chapter 21. The
special proportioning and detailing provisions of Chapter 21are intended to provide a monolithic reinforced concretestructure with adequate toughness to respond inelasticallyunder severe earthquake motions. See also R21.2.1.
1.1.8.3 Seismic risk level of a region shall be reg-ulated by the legally adopted general building code ofwhich this code forms a part, or determined by localauthority.

R1.1.8.3 Definition of low, moderate, and high seis-mic risk as used by ACI 350 are not precise. Seismic risklevel is usually designated by zones or areas of equal proba-bility of risk of damage, related to the intensity of groundshaking, such as Zone 0no damage; Zone 1minor dam-

ures Code and Commentary

CHAPTER 1 350/350R-13

CODE COMMENTARY


age; Zone 2moderate damage; and Zones 3 and 4majordamage. The tabulation is provided only as guide in inter-preting the requirements of 1.1.8. The correlations impliedare neither precise nor inflexible. Seismic risk levels (Seis-mic Zone Maps) are under the jurisdiction of a generalbuilding code rather than ACI 350. In the absence of a gen-eral building code that addresses earthquake loads and seis-mic zoning, it is the intent of Committee 350 that the localauthorities (engineers, geologists, and building code offi-cials) should decide on proper need and application of thespecial provisions for seismic design. Seismic zoning maps,such as recommended in References 1.9 and 1.10, are suit-able for correlating seismic risk.

1.1.9 For prestressed concrete environmental struc-tures, Chapter 1 through Chapter 21 cover prestressing
in general. Chapter 1 through Chapter 21 plus Appen-dix F cover the use of circular wire and strand wrappedprestressed concrete environmental structures.
R1.1.9 Appendix F is incorporated to address those aspects
of circular wrapped prestressed concrete environmental struc-tures that are not directly covered within the main body of thecode. Thus, Appendix F deals with items that are unique tocircular wrapped prestressed structures, such as steel dia-phragm, wrapped prestressing and shotcrete.
1.2 Drawings and specifications
R1.2 Drawings and specifications
1.2.1 Copies of design drawings, typical details, andspecifications for all structural concrete constructionshall bear the seal of a registered engineer or architect.These drawings, details, and specifications shall show:

(a) Name and date of issue of code and supplementto which design conforms

(b) Live load and other loads used in design

(c) Specified compressive strength of concrete atstated ages or stages of construction for which eachpart of structure is designed

(d) Specified strength or grade of reinforcement

(e) Size and location of all structural elements andreinforcement

(f) Provision for dimensional changes resulting fromcreep, shrinkage, and temperature

(g) Magnitude and location of prestressing forces

(h) Anchorage length of reinforcement and locationand length of lap splices

(i) Type and location of welded splices and mechani-cal connections of reinforcement

(j) Details and location of all contraction or isolationjoints specified for plain concrete in Chapter 22

(k) The design liquid level for any structure designedto contain liquid

(l) Concrete properties and ingredients includingtype of cement, water-cementitious materials ratio,and, if allowed, admixtures, additives, and pozzolans

R1.2.1 The provisions for preparation of design drawingsand specifications are, in general, consistent with those ofmost general building codes and are intended as supplementsthereto.

The code lists some of the more important items of informa-tion that must be included in the design drawings, details, orspecifications. The code does not imply an all inclusive list,and additional items may be required by the building official.


350/350R-14 CHAPTER 1

COMMENTARY
CODE(m) Additional requirements, such as limitations ondrying shrinkage
(n) Requirements for liquid-tightness testing, includ-ing liquid-tightness testing before backfilling.

1.2.2 Calculations pertinent to design shall be filedwith the drawings when required by the building official.Analyses and designs using computer programs shallbe permitted provided design assumptions, user input,and computer-generated output are submitted. Modelanalysis shall be permitted to supplement calculations.


R1.2.2 Documented computer output is acceptable inlieu of manual calculations. The extent of input and outputinformation required will vary, according to the specificrequirements of individual building officials. However,when a computer program has been used by the designer,only skeleton data should normally be required. This shouldconsist of sufficient input and output data and other infor-mation to allow the building official to perform a detailedreview and make comparisons using another program ormanual calculations. Input data should be identified as tomember designation, applied loads, and span lengths. Therelated output data should include member designation andthe shears, moments, and reactions at key points in the span.For column design, it is desirable to include moment magni-fication factors in the output where applicable.

The code permits model analysis to be used to supplementstructural analysis and design calculations. Documentationof the model analysis should be provided with the relatedcalculations. Model analysis should be performed by anengineer or architect having experience in this technique.

1.2.3 Building official means the officer or otherdesignated authority charged with the administrationand enforcement of this code, or his duly authorizedrepresentative.

R1.2.3 Building official is the term used by many gen-eral building codes to identify the person charged withadministration and enforcement of the provisions of thebuilding code. However, such terms as building commis-sioner or building inspector are variations of the title,and the term building official as used in this code isintended to include those variations as well as others whichare used in the same sense.

1.3 Inspection

tu

R1.3 Inspection

The quality of concrete structures depends largely on work-manship in construction. The best of materials and designpractice will not be effective unless the construction is per-formed well. Inspection is provided to assure satisfactorywork in accordance with the design drawings and specifica-tions. Proper performance of the structure depends on con-struction which accurately represents the design and meetscode requirements, within the tolerances allowed. In thepublic interest, local building ordinances should require theowner to provide inspections.

1.3.1 As a minimum, concrete construction shall beinspected as required by the legally adopted generalbuilding code. In the absence of such requirements,concrete construction shall be inspected throughoutthe various work stages by an engineer or architect, orby a competent representative responsible to thatengineer or architect.

R1.3.1 Inspection of construction by or under the super-vision of the engineer or architect responsible for the designshould be considered because the person in charge of thedesign is the best qualified to inspect for conformance withthe design. When such an arrangement is not feasible, theowner may provide proper inspection of constructionthrough his engineers or architects or through separateinspection organizations with demonstrated capability forperforming the inspection.

res Code and Commentary

CHAPTER 1 350/350R-15

CODE COMMENTARY

ACI 350 Environmental Stru

The building departments having jurisdiction over the con-struction may have the necessary expertise and capability toinspect structural concrete construction.

When inspection is done independently of the designer, it isrecommended that the designer be employed to at leastoversee inspection and observe the work to see that hisdesign requirements are properly executed.

In some jurisdictions, legislation has established special regis-tration or licensing procedures for persons performing certaininspection functions. A check should be made in the generalbuilding code or with the building official to ascertain if anysuch requirements exist within a specific jurisdiction.

Inspection responsibility and the degree of inspectionrequired should be set forth in the contracts between theowner, architect, engineer, and contractor. Adequate feesshould be provided consistent with the work and equipmentnecessary to properly perform the inspection.

1.3.2 The inspector shall require compliance withdesign drawings and specifications. Unless specifiedotherwise in the legally adopted general building code,inspection records shall include:

(a) Quality and proportions of concrete materialsand strength of concrete

(b) Construction and removal of forms and reshoring

(c) Placing of reinforcement

(d) Mixing, placing, and curing of concrete

(e) Sequence of erection and connection of precastmembers

(f) Tensioning of prestressing tendons

(g) Any significant construction loadings on com-pleted floors, members, or walls

(h) General progress of work.

ct

R1.3.2 By inspection, the code does not mean that theinspector should supervise the construction. Rather it meansthat the one employed for inspection should visit the projectwith the frequency necessary to observe the various stagesof work and ascertain that it is being done in compliancewith contract documents and code requirements. The fre-quency should be at least enough to provide general knowl-edge of each operation, whether this be several times a dayor once in several days.

Inspection in no way relieves the contractor from his obliga-tion to follow the plans and specifications implicitly and toprovide the designated quality and quantity of materials andworkmanship for all job stages. The inspector should bepresent as frequently as he/she deems necessary to judgewhether the quality and quantity of the work complies withthe contract documents; to counsel on possible ways ofobtaining the desired results; to see that the general systemproposed for formwork appears proper (though it remainsthe contractor's responsibility to design and build adequateforms and to leave them in place until it is safe to removethem); to see that reinforcement is properly installed; to seethat concrete is of the correct quality, properly placed, andcured; and to see that tests for quality control are beingmade as specified.

The code prescribes minimum requirements for inspectionof all structures within its scope. It is not a constructionspecification and any user of the code may require higherstandards of inspection than cited in the legal code if addi-tional requirements are necessary.

Recommended procedures for organization and conduct ofconcrete inspection are given in detail in Guide for Con-

crete Inspection.1.11 (Sets forth procedures relating toconcrete construction to serve as a guide to owners, archi-tects, and engineers in planning an inspection program.)


350/350R-16 CHAPTER 1

CODE COMMENTARY


Detailed methods of inspecting concrete construction aregiven in ACI Manual of Concrete Inspection (SP-2)

reported by ACI Committee 311.1.12 (Describes methods ofinspecting concrete construction which are generally acceptedas good practice. Intended as a supplement to specificationsand as a guide in matters not covered by specifications.)

1.3.3 When the ambient temperature falls below 40 For rises above 95 F, a record shall be kept of concretetemperatures and of protection given to concrete dur-ing placement and curing.

R1.3.3 The term ambient temperature means the tem-perature of the environment to which the concrete is directlyexposed. Concrete temperature as used in this section maybe taken as the air temperature near the surface of the con-crete; however, during mixing and placing it is practical tomeasure the temperature of the mixture.

1.3.4 Records of inspection required in 1.3.2 and1.3.3 shall be preserved by the inspecting engineer orarchitect for 2 years after completion of the project.

R1.3.4 A record of inspection in the form of a job diaryis required in case questions subsequently arise concerningthe performance or safety of the structure or members. Pho-tographs documenting job progress may also be desirable.

Records of inspection must be preserved for at least 2 yearsafter the completion of the project. The completion of theproject is the date at which the owner accepts the project, orwhen a certificate of occupancy is issued, whichever date islater. The general building code or other legal requirementsmay require a longer preservation of such records.

1.3.5 For moment frames resisting seismic loads instructures designed in conformance with Chapter 21and located in regions of high seismic risk, a speciallyqualified inspector under the supervision of the personresponsible for the structural design shall provide con-tinuous inspection for the placement of the reinforce-ment and concrete.

t

R1.3.5 The purpose of this section is to assure that the spe-cial detailing required in concrete ductile frames is properlyexecuted through inspection by personnel who are qualifiedto do this work. Qualifications of inspectors should be deter-mined by the jurisdiction enforcing the general building code.

1.4 Approval of special systems of design or construction

Sponsors of any system of design or constructionwithin the scope of this code, the adequacy of whichhas been shown by successful use or by analysis ortest, but which does not conform to or is not coveredby this code, shall have the right to present the data onwhich their design is based to the building official or toa board of examiners appointed by the building official.This board shall be composed of competent engineersand shall have authority to investigate the data so sub-mitted, to require tests, and to formulate rules govern-ing design and construction of such systems to meetthe intent of this code. These rules when approved bythe building official and promulgated shall be of thesame force and effect as the provisions of this code.

R1.4 Approval of special systems of design or construction

New methods of design, new materials, and new uses ofmaterials must undergo a period of development beforebeing specifically covered in a code. Hence, good systemsor components might be excluded from use by implication ifmeans were not available to obtain acceptance.

For special systems considered under this section, specifictests, load factors, deflection limits, and other pertinentrequirements should be set by the board of examiners, andshould be consistent with the intent of the code.

The provisions of this section do not apply to model testsused to supplement calculations under 1.2.2 or to strengthevaluation of existing structures under Chapter 20.


CHAPTER 2 350/350R-17

CHAPTER 2 DEFINITIONS

CODE COMMENTARY

2.1 The following terms are defined for general usein this code. Specialized definitions appear in individ-ual chapters.


R2.1 For consistent application of the code, it is neces-sary that terms be defined where they have particular mean-ings in the code. The definitions given are for use inapplication of this code only and do not always correspondto ordinary usage. A glossary of most used terms relating tocement manufacturing, concrete design and construction,and research in concrete is contained in Cement and Con-

crete Terminology reported by ACI Committee 116.2.1

By code definition, sand-lightweight concrete is structurallightweight concrete with all of the fine aggregate replacedby sand. This definition may not be in agreement with usageby some material suppliers or contractors where the major-ity, but not all, of the lightweight fines are replaced by sand.For proper application of the code provisions, the replace-ment limits must be stated, with interpolation when partialsand replacement is used.

Deformed reinforcement is defined as that meeting thedeformed bar specifications of 3.5.3.1, or the specifications
of 3.5.3.3, 3.5.3.4, 3.5.3.5, or 3.5.3.6. No other bar or fabricqualifies. This definition permits accurate statement ofanchorage lengths. Bars or wire not meeting the deforma-tion requirements or fabric not meeting the spacing require-ments are plain reinforcement, for code purposes, andmay be used only for spirals.
A number of definitions for loads are given as the code con-tains requirements that must be met at various load levels.The terms dead load and live load refer to the unfactoredloads (service loads) specified or defined by the generalbuilding code. Service loads (loads without load factors) areto be used where specified in the code to proportion or inves-tigate members for adequate serviceability as in 9.5, Control
of Deflections. Loads used to proportion a member for ade-quate strength are defined as factored loads. Factored loadsare service loads multiplied by the appropriate load factorsspecified in 9.2 for required strength. The term designloads, as used in the 1971 ACI 318 code edition to refer toloads multiplied by appropriate load factors, was discontin-ued in the 1977 ACI 318 code to avoid confusion with thedesign load terminology used in general building codes todenote service loads, or posted loads in buildings. The fac-tored load terminology, first adopted in the 1977 ACI 318code, clarifies when the load factors are applied to a particularload, moment, or shear value as used in the code provisions.
Reinforced concrete is defined to include prestressed con-crete. Although the behavior of a prestressed member withunbonded tendons may vary from that of members withcontinuously bonded tendons, bonded and unbonded pre-stressed concrete are combined with conventionally rein-forced concrete under the generic term reinforced con-


350/350R-18 CHAPTER 2

CODE COMMENTARY


crete. Provisions common to both prestressed and conven-tionally reinforced concrete are integrated to avoid overlap-ping and conflicting provisions.

Strength of a member or cross section calculated using stan-dard assumptions and strength equations, and nominal(specified) values of material strengths and dimensions isreferred to as nominal strength. The subscript n is used todenote the nominal strengths; nominal axial load strengthPn , nominal moment strength Mn , and nominal shearstrength Vn. Design strength or usable strength of a mem-ber or cross section is the nominal strength reduced by thestrength reduction factor .

The required axial load, moment, and shear strengths used toproportion members are referred to either as factored axialloads, factored moments, and factored shears, or required axialloads, moments, and shears. The factored load effects are cal-culated from the applied factored loads and forces in such loadcombinations as are stipulated in the code (see 9.2).

The subscript u is used only to denote the requiredstrengths; required axial load strength Pu, required momentstrength Mu, and required shear strength Vu, calculatedfrom the applied factored loads and forces.

The basic requirement for strength design may be expressedas follows:

Design strength Required strength

Pn Pu

Mn Mu

Vn Vu

For additional discussion on the concepts and nomenclaturefor strength design see commentary Chapter 9.

The term compression member is used in the code to defineany member in which the primary stress is longitudinal com-pression. Such a member need not be vertical but may haveany orientation in space. Bearing walls, columns, and pedes-tals qualify as compression members under this definition.

The differentiation between columns and walls in the codeis based on the principal use rather than on arbitrary rela-tionships of height and cross-sectional dimensions. Thecode, however, permits walls to be designed using the prin-ciples stated for column design (see 14.4), as well as by theempirical method (see 14.5).

While a wall always encloses or separates spaces, it mayalso be used to resist horizontal or vertical forces or bend-ing. For example, a retaining wall or a basement wall alsosupports various combinations of loads.

A column is normally used as a main vertical member carry-ing axial loads combined with bending and shear. It may,however, form a small part of an enclosure or separation.


CHAPTER 2 350/350R-19

CODE COMMENTARY


An ideal backer rod will permit compression to one-half itsoriginal width and will re-expand to fill the joint when the adja-cent members contract. Neoprene and open or closed cell plas-tic foams are satisfactory materials for backer rods. The backerrod should be compatible with the adjacent joint sealant.

Admixture Material other than water, aggregate, orhydraulic cement, used as an ingredient of concreteand added to concrete before or during its mixing tomodify its properties.

Aggregate Granular material, such as sand, gravel,crushed stone, and iron blast-furnace slag, used witha cementing medium to form a hydraulic cement con-crete or mortar.

Aggregate, lightweight Aggregate with a dry,loose weight of 70 lb/ft3 or less.

Anchorage In post-tensioning, a device used toanchor tendon to concrete member; in pretensioning,a device used to anchor tendon during hardening ofconcrete.

Backer rod A compressible rod placed betweenjoint filler and sealant and used to provide support forand to control the depth of sealant.

Bonded tendon Prestressing tendon that isbonded to concrete either directly or through grouting.

Building official See 1.2.3.

Cementitious materials Materials as specified inChapter 3, which have cementing value when used inconcrete either by themselves, such as portlandcement, blended hydraulic cements, and expansivecement, or such materials in combination with fly ash,other raw or calcined natural pozzolans, silica fume,and/or ground granulated blast-furnace slag.

Column Member with a ratio of height-to-least lat-eral dimension exceeding 3 used primarily to supportaxial compressive load.

Composite concrete flexural members Concreteflexural members of precast and/or cast-in-place con-crete elements constructed in separate placementsbut so interconnected that all elements respond toloads as a unit.

Concrete Mixture of portland cement or any otherhydraulic cement, fine aggregate, coarse aggregate,and water, with or without admixtures.

Concrete, specified compressive strength of, (fc) Compressive strength of concrete used in design andevaluated in accordance with provisions of Chapter 5,expressed in pounds per square inch (psi). Wheneverthe quantity fc is under a radical sign, square root ofnumerical value only is intended, and result has unitsof pounds per square inch (psi).


350/350R-20 CHAPTER 2

CODE COMMENTARY
Concrete, structural lightweight Concrete con-taining lightweight aggregate that conforms to 3.3 andhas an air-dry unit weight as determined by TestMethod for Unit Weight of Structural Lightweight Con-
crete (ASTM C 567), not exceeding 115 lb/ft3. In thiscode, a lightweight concrete without natural sand istermed all-lightweight concrete and lightweight con-crete in which all of the fine aggregate consists of nor-mal weight sand is termed sand-lightweight concrete.

Contraction joint Formed, sawed, or tooled groovein a concrete structure to create a weakened planeand regulate the location of cracking resulting from thedimensional change of different parts of the structure.

Curvature friction Friction resulting from bends orcurves in the specified prestressing tendon profile.

Deformed reinforcement Deformed reinforcing bars,bar mats, deformed wire, welded plain wire fabric, andwelded deformed wire fabric conforming to 3.5.3.

Development length Length of embedded rein-forcement required to develop the design strength ofreinforcement at a critical section. See 9.3.3.

Effective depth of section (d) Distance measuredfrom extreme compression fiber to centroid of tensionreinforcement.

Effective prestress Stress remaining in prestress-ing tendons after all losses have occurred, excludingeffects of dead load and superimposed load.

Embedment length Length of embedded rein-forcement provided beyond a critical section.

Environmental durability factor A factor used inaddition to load factors to produce concrete designsapproximately similar to concrete designs by the Alter-nate Design Method.

Extreme tension steel The reinforcement (pre-stressed or nonprestressed) that is the farthest fromthe extreme compression fiber.

Isolation joint A separation between adjoiningparts of a concrete structure, usually a vertical plane,at a designed location such as to interfere least withperformance of the structure, yet such as to allow rela-tive movement in three directions and avoid formationof cracks elsewhere in the concrete and through whichall or part of the bonded reinforcement is interrupted.

Jacking force In prestressed concrete, temporaryforce exerted by device that introduces tension intoprestressing tendons.

ACI 350 Environmental Structu

Refer to Chapter 9 of this code for rules on the applicationof this factor.


CHAPTER 2 350/350R-21

CODE COMMENTARY
Joint filler A compressible, preformed materialused to fill an expansion joint to prevent the infiltrationof debris and to provide support for backer rod andsealants.
Joint sealant A synthetic elastomeric material usedto finish a joint and to exclude solid foreign materials.

Load, dead Dead weight supported by a member,as defined by general building code of which this codeforms a part (without load factors).

Load, factored Load, multiplied by appropriate loadfactors, used to proportion members by the strengthdesign method of this code. See 8.1.1 and 9.2.

Load, live Live load specified by general buildingcode of which this code forms a part (without loadfactors).

Load, service Load specified by general buildingcode of which this code forms a part (without loadfactors).

Modulus of elasticity Ratio of normal stress to cor-responding strain for tensile or compressive stressesbelow proportional limit of material. See 8.5.

Net tensile strain The tensile strain at nominalstrength exclusive of strains due to effective prestress,creep, shrinkage, and temperature.

Pedestal Upright compression member with a ratioof unsupported height to average least lateral dimen-sion of less than 3.

Plain concrete Structural concrete with no rein-forcement or with less reinforcement than the minimumamount specified for reinforced concrete.

Plain reinforcement Reinforcement that does not con-form to definition of deformed reinforcement. See 3.5.4.

Post-tensioning Method of prestressing in whichtendons are tensioned after concrete has hardened.

Precast concrete Structural concrete element castelsewhere than its final position in the structure.

Prestressed concrete Structural concrete in whichinternal stresses have been introduced to reduce poten-tial tensile stresses in concrete resulting from loads.

Pretensioning Method of prestressing in which ten-dons are tensioned before concrete is placed.

Reinforced concrete Structural concrete reinforcedwith no less than the minimum amounts of prestressingtendons or nonprestressed reinforcement specified inChapters 1 through 21 and Appendices A, F, and G.


Cork, neoprene, rubber, foam, and other materials conform-ing to ASTM D 1056 and D 1752 are satisfactory joint fillers.The preformed filler should be compatible with adjacentjoint sealant.

Sealants used in water treatment plants, reservoirs, andother structural facilities that will be in contact with potablewater should be certified as compliant with ANSI/NSF 61.In addition, the sealant should be resistant to chlorinatedwater and suitable for immersion service.


350/350R-22 CHAPTER 2

CODE COMMENTARY
Reinforcement Material that conforms to 3.5, exclud-ing prestressing tendons unless specifically included.
Reshores Shores placed snugly under a concreteslab or other structural member after the original formsand shores have been removed from a larger area, thusrequiring the new slab or structural member to deflectand support its own weight and existing constructionloads applied prior to the installation of the reshores.

Shores Vertical or inclined support membersdesigned to carry the weight of the formwork, con-crete, and construction loads above.

Span length See 8.7.

Spiral reinforcement Continuously wound rein-forcement in the form of a cylindrical helix.

Splitting tensile strength (fct) Tensile strength ofconcrete determined in accordance with ASTM C 496as described in Specification for Lightweight Aggre-gates for Structural Concrete (ASTM C 330).

Stirrup Reinforcement used to resist shear and tor-sion stresses in a structural member; typically bars,wires, or welded wire fabric (plain or deformed) eithersingle leg or bent into L, U, or rectangular shapes andlocated perpendicular to or at an angle to longitudinalreinforcement. (The term stirrups is usually applied tolateral reinforcement in flexural members and the termties to those in compression members.) See also Tie.

Strength, design Nominal strength multiplied by astrength reduction factor . See 9.3.

Strength, nominal Strength of a member or crosssection calculated in accordance with provisions andassumptions of the strength design method of thiscode before application of any strength reduction fac-tors. See 9.3.1.

Strength, required Strength of a member or crosssection required to resist factored loads or relatedinternal moments and forces in such combinations asare stipulated in this code. See 9.1.1.

Stress Intensity of force per unit area.

Structural concrete All concrete used for structuralpurposes including plain and reinforced concrete.

Tendon Steel element such as wire, cable, bar, rod,or strand, or a bundle of such elements, used to impartprestress to concrete.

Tie Loop of reinforcing bar or wire enclosing longi-tudinal reinforcement. A continuously wound bar orwire in the form of a circle, rectangle, or other polygonshape without re-entrant corners is acceptable. Seealso Stirrup.


CHAPTER 2 350/350R-23

CODE COMMENTARY
Transfer Act of transferring stress in prestressingtendons from jacks or pretensioning bed to concretemember.
Wall Member, usually vertical, used to enclose orseparate spaces.

Waterstop A continuous preformed strip of metal,rubber, plastic, or other material inserted across a jointto prevent the passage of liquid through the joint.

Wobble friction In prestressed concrete, frictioncaused by unintended deviation of prestressing sheathor duct from its specified profile.

Yield strength Specified minimum yield strength oryield point of reinforcement in pounds per square inch.Yield strength or yield point shall be determined in ten-sion according to applicable ASTM standards as mod-ified by 3.5 of this code.


Waterstops are available in various sizes, shapes, and materials.Environmental concrete structures commonly use waterstopsof preformed rubber or polyvinyl chloride with a minimumthickness of 3/8 in. They should normally be at least 9 in. widefor expansion joints and 6 in. wide for other types of joints toprovide adequate embedment in the concrete. Metal water-stops are used for special exposure environments. Expansiverubber or adhesive waterstops may be used in joints castagainst previously placed concrete, or in new constructionwhen approved by the engineer. Chemical resistance, jointmovement capacity, and design temperature range are amongthe items that should be investigated when selecting water-stops. Joint details are further described in ACI 350.4R.


350/350R-24 CHAPTER 2

CODE COMMENTARY


Notes

CHAPTER 3 350/350R-25

PART 2 STANDARDS FOR TESTS ANDMATERIALS

CHAPTER 3 MATERIALS

CODE COMMENTARY
3.0 Notation
fy = specified yield strength of nonprestressed rein-forcement, psi

3.1 Tests of materials

ACI 350 Environmental Structu

R3.1 Tests of materials

3.1.1 Building official shall have the right to ordertesting of any materials used in concrete constructionto determine if materials are of quality specified.

3.1.2 Tests of materials and of concrete shall bemade in accordance with standards listed in 3.8.

3.1.3 A complete record of tests of materials and ofconcrete shall be available for inspection duringprogress of work and for 2 years after completion ofthe project, and shall be preserved by inspecting engi-neer or architect for that purpose.

R3.1.3 The record of tests of materials and of concretemust be preserved for at least 2 years after completion of theproject. Completion of the project is the date at which theowner accepts the project or when the certificate of occu-pancy is issued, whichever date is later. Local legal require-ments may require longer preservation of such records.

3.2 Cements
R3.2 Cements
3.2.1 Cement shall conform to one of the followingspecifications:

(a) Specification for Portland Cement (ASTM C 150).

(b) Specification for Blended Hydraulic Cements(ASTM C 595), excluding Types S and SA which arenot intended as principal cementing constituents ofstructural concrete.

(c) Specification for Expansive Hydraulic Cement(ASTM C 845).

R3.2.1 Different cements or cements from different pro-ducers should not be used interchangeably in the same ele-ment or portion of the work. Additional guidance on cement

may be found in ACI 225R.3.1

Concrete made with expansive cement can be used to reducedrying-shrinkage cracking in environmental engineeringconcrete structures, but the ACI 350 committee is not yet in aposition to recommend detailed requirements for its use. Forthe design to be successful, the engineer must recognize thecharacteristics and properties of shrinkage-compensating

concrete and cement as described in ACI 2233.2 and ASTMC 845 (Type E1-K), respectively. Type K cement has histori-cally shown very satisfactory resistance to sulfate attack inboth the laboratory and the field. Additional care and controlshould be exercised during design and construction. Detailedinformation on shrinkage-compensating concrete is con-tained in ACI 223.

3.2.2 Cement used in the work shall correspond tothat on which selection of concrete proportions wasbased. See 5.2.

R3.2.2 Depending on the circumstances, the provision of3.2.2 may require only the same type of cement or mayrequire cement from the identical source. The latter would

be the case if the standard deviation3.3 of strength tests usedin establishing the required strength margin was based on acement from a particular source. If the standard deviationwas based on tests involving a given type of cementobtained from several sources, the former interpretationwould apply.


350/350R-26 CHAPTER 3

CODE COMMENTARY
3.3 Aggregates

R3.3 Aggregates

3.3.1 Concrete aggregates shall conform to one ofthe following specifications:

(a) Specification for Concrete Aggregates (ASTMC 33).

(b) Specification for Lightweight Aggregates forStructural Concrete (ASTM C 330).

Exception: Aggregates which have been shown byspecial test or actual service to produce concrete ofadequate strength and durability and approved by thebuilding official.

R3.3.1 It is recognized that aggregates conforming to theASTM specifications are not always economically availableand that, in some instances, noncomplying materials have along history of satisfactory performance. Such nonconform-ing materials are permitted with special approval whenacceptable evidence of satisfactory performance is pro-vided. It should be noted, however, that satisfactory perfor-mance in the past does not guarantee good performanceunder other conditions and in other localities. Wheneverpossible, aggregates conforming to the designated specifica-tions should be used.

aggregate may be waived.

3.3.2 Nominal maximum size of coarse aggregateshall be not larger than:

(a) 1/5 the narrowest dimension between sides offorms, nor

(b) 1/3 the depth of slabs, nor

(c) 3/4 the minimum clear spacing between individ-ual reinforcing bars or wires, bundles of bars, or pre-stressing tendons or ducts.

These limitations shall not apply if, in the judgment ofthe engineer, workability and methods of consolidationare such that concrete can be placed without honey-comb or voids.

R3.3.2 The size limitations on aggregates are provided toensure proper encasement of reinforcement and to minimizehoneycomb. Note that the limitations on maximum size ofthe aggregate may be waived if, in the judgment of the engi-neer, the workability and methods of consolidation of theconcrete are such that the concrete can be placed withouthoneycomb or voids. In this instance, the engineer mustdecide whether or not the limitations on maximum size of

3.3.3 Where aggregates are alkali-reactive, imposerestrictions on materials to minimize deterioration.

R3.3.3 Alkali-aggregate reactions can cause an expan-sive action when reactive aggregates come in contact withalkali hydroxides in the hardened concrete. These reactionscan result in long-term deterioration of concrete, usually theinterior of the concrete. It is recommended to specify testingand quality aggregates, conforming to ASTM C 33.

Reactivity testing of aggregates should be required whenlocal aggregates are suspected of being alkali reactive.Unless all local aggregates are known to be nonreactive, alow-alkali cement should be used. Pozzolans and lithiumhydroxide admixtures may also be considered. However, theuse of lithium hydroxide admixtures to control reactiveaggregates is technology that is not widely accepted at thistime.

Alkali-aggregate reactivity potential should be determinedfor local aggregates when local aggregates are suspected ofbeing alkali reactive. On projects where alkali reactivity is aknown problem, prescreening of aggregate sources beforecompleting design of the project, may be advisable.

Aggregates that do not indicate a potential for alkali reactiv-ity or reactive constituents may be used without further test-ing. Aggregates that indicate a potential for alkali reactivityshould be tested for potential reactivity using the mortar-bartest, ASTM C 227 and ASTM C 289. Nonreactive aggre-gates may need to be imported if local aggregates exhibitunacceptable potential reactivity.


CHAPTER 3 350/350R-27

CODE COMMENTARY

3.5 Steel reinforcement

3.4 Water


R3.4 Water

3.4.1 Water used in mixing concrete shall be cleanand free from injurious amounts of oils, acids, alkalis,salts, organic materials, or other substances deleteri-ous to concrete or reinforcement.

R3.4.1 Almost any natural water that is drinkable (pota-ble) and has no pronounced taste or odor is satisfactory asmixing water for making concrete. Impurities in mixingwater, when excessive, may affect not only setting time,concrete strength, and volume stability (length change), butmay also cause efflorescence or corrosion of reinforcement.Where possible, water with high concentrations of dissolvedsolids should be avoided.

Salts, or other deleterious substances contributed from theaggregate or admixtures are additive to the amount whichmight be contained in the mixing water. These additionalamounts must be considered in evaluating the acceptability ofthe total impurities that may be deleterious to concrete or steel.

3.4.2 Mixing water for prestressed concrete or forconcrete that will contain aluminum embedments,including that portion of mixing water contributed in theform of free moisture on aggregates, shall not containdeleterious amounts of chloride ion. See 4.4.1.

3.4.3 Nonpotable water shall not be used in con-crete unless the following are satisfied:

3.4.3.1 Selection of concrete proportions shall bebased on concrete mixes using water from the samesource.

3.4.3.2 Mortar test cubes made with nonpotablemixing water shall have 7-day and 28-day strengthsequal to at least 90 percent of strengths of similarspecimens made with potable water. Strength testcomparison shall be made on mortars, identical exceptfor the mixing water, prepared and tested in accor-dance with Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens) (ASTM C 109).

R3.5 Steel reinforcement

3.5.1 Reinforcement shall be deformed reinforce-ment, except that plain reinforcement shall be permit-ted for spirals or tendons; and reinforcement con-sisting of structural steel, steel pipe, or steel tubingshall be permitted as specified in this code.

R3.5.1 Materials permitted for use as reinforcement arespecified. Other metal elements, such as inserts, anchorbolts, or plain bars for dowels at isolation or contractionjoints, are not normally considered to be reinforcementunder the provisions of this code.

3.5.2 Welding of reinforcing bars shall conform toStructural Welding Code Reinforcing Steel, ANSI/AWS D1.4 of the American Welding Society. Type andlocation of welded splices and other required weldingof reinforcing bars shall be indicated on the designdrawings or in the project specifications. ASTM rein-forcing bar specifications, except for ASTM A 706,shall be supplemented to require a report of materialproperties necessary to conform to the requirements inANSI/AWS D1.4.

R3.5.2 When welding of reinforcing bars is required, theweldability of the steel and compatible welding proceduresneed to be considered. The provisions in ANSI/AWS D1.4Welding Code cover aspects of welding reinforcing bars,including criteria to qualify welding procedures.

Weldability of the steel is based on its chemical compositionor carbon equivalent (CE). The Welding Code establishespreheat and interpass temperatures for a range of carbonequivalents and reinforcing bar sizes. Carbon equivalent is


350/350R-28 CHAPTER 3

CODE COMMENTARY


calculated from the chemical composition of the reinforcingbars. The Welding Code has two expressions for calculatingcarbon equivalent. A relatively short expression, consider-ing only the elements carbon and manganese, is to be usedfor bars other than ASTM A 706 material. A more compre-hensive expression is given for ASTM A 706 bars. The CEformula in the Welding Code for A 706 bars is identical tothe CE formula in the ASTM A 706 specification.

The engineer should realize that the chemical analysis, forbars other than A 706, required to calculate the carbonequivalent is not routinely provided by the producer of thereinforcing bars. Hence, for welding reinforcing bars otherthan A 706 bars, the design drawings or project specifica-tions should specifically require results of the chemicalanalysis to be furnished.

The ASTM A 706 specification covers low-alloy steel rein-forcing bars intended for applications requiring controlledtensile properties or welding. Weldability is accomplishedin the A 706 specification by limits or controls on chemical

composition and on carbon equivalent.3.4 The producer isrequired by the A 706 specification to report the chemicalcomposition and carbon equivalent.

The ANSI/AWS D1.4 Welding Code requires the contractorto prepare written welding procedure specifications conform-ing to the requirements of the Welding Code. Appendix A ofthe Welding Code contains a suggested form which shows theinformation required for such a specification for each jointwelding procedure.

Often it is necessary to weld to existing reinforcing bars ina structure when no mill test report of the existing rein-forcement is available. This condition is particularly com-mon in alterations or building expansions. ANSI/AWSD1.4 states for such bars that a chemical analysis may beperformed on representative bars. If the chemical compo-sition is not known or obtained, the Welding Code requiresa minimum preheat. For bars other than A 706 material,the minimum preheat required is 300 F for bars No. 6 orsmaller, and 400 F for No. 7 bars or larger. The requiredpreheat for all sizes of A 706 is to be the temperature givenin the Welding Codes table for minimum preheat corre-sponding to the range of CE over 45 percent to 55 per-cent. Welding of the particular bars must then beperformed in accordance with ANSI/AWS D 1.4. It shouldalso be determined if additional precautions are in order,based on other considerations such as stress level in thebars, consequences of failure, and heat damage to existingconcrete due to welding operations.

Welding of wire to wire, and of wire or welded wire fabricto reinforcing bars or structural steel elements is not coveredby ANSI/AWS D1.4. If welding of this type is required on aproject, the engineer should specify requirements or perfor-mance criteria for this welding. If cold drawn wires are to bewelded, the welding procedures should address the poten-tial loss of yield strength and ductility, achieved by the


CHAPTER 3 350/350R-29

CODE COMMENTARY

3.5.3.1 Deformed reinforcing bars shall conformto one of the following specifications:

(a) Specification for Deformed and Plain Billet-SteelBars for Concrete Reinforcement (ASTM A 615).

(b) Specification for Rail-Steel Deformed and PlainBars for Concrete Reinforcement including Supple-mentary Requirement S1 (ASTM A 616 including S1).

(c) Specification for Axle-Steel Deformed and PlainBars for Concrete Reinforcement (ASTM A 617).

(d) Specification for Low-Alloy Steel Deformed Barsfor Concrete Reinforcement (ASTM A 706).

3.5.3.3 Bar mats for concrete reinforcement shallconform to Specification for Fabricated DeformedSteel Bar Mats for Concrete Reinforcement (ASTM A184). Reinforcing bars used in bar mats shall conformto one of the specifications listed in 3.5.3.1.

3.5.3.4 Deformed wire for concrete reinforce-ment shall conform to Specification for Steel Wire,Deformed, for Concrete Reinforcement (ASTM A496), except that wire shall not be smaller than size D4

3.5.3 Deformed reinforcement


cold working process (during manufacture), when such wiresare heated by welding. Machine and resistance welding asused in the manufacture of welded wire fabrics is covered byASTM A 185 and A 497 and is not part of this concern.

R3.5.3 Deformed reinforcement

u

R3.5.3.1 ASTM A 615 covers specifications fordeformed billet-steel reinforcing bars which are normallyused in reinforced concrete construction in the UnitedStates. The specification also requires that all billet-steelreinforcing bars be marked with the letter S.

Rail-steel reinforcing bars used with this code must conformto ASTM A 616 including Supplementary Requirement S1,marked with the letter R, in addition to the rail symbol. S1 pre-scribes more restrictive requirements for bend tests.

ASTM A 706 covers low-alloy steel deformed bars in-tended for special applications where welding or bending,or both, are of importance. The specification requires thatthe bars be marked with the letter W for type of steel.

3.5.3.2 Deformed reinforcing bars with a speci-fied yield strength fy exceeding 60,000 psi shall bepermitted, provided fy shall be the stress correspond-ing to a strain of 0.35 percent and the bars otherwiseconform to one of the ASTM specifications listed in3.5.3.1. See 9.4.

R3.5.3.2 ASTM A 615 includes provisions for Grade75 bars in sizes No. 6 through 18.

Date post:	30-Mar-2018
Category:	Documents
Upload:	vanduong
View:	582 times
Download:	55 times

350-01/350R-01 CODE REQUIREMENTS FOR ENVIRONMENTAL ...civilwares.free.fr/ACI/MCP04/350_01.pdf ·...

Documents