BUILDING CODE REQUIREMENTS FOR STRUCTURAL CONCRETE (ACI 318-02) AND COMMENTARY (ACI 318R-02) REPORTED BY ACI COMMITTEE 318 ACI Committee 318 Structural Building Code James R. Cagley Basile G. Rabbat Chairman Secretary Craig E. Barnes S. K. Ghosh Cary S. Kopczynski Jack P. Moehle Florian G. Barth Hershell Gill James Lefter Glen M. Ross Roger J. Becker David P. Gustafson H. S. Lew Charles G. Salmon Kenneth B. Bondy James R. Harris James G. MacGregor Mete A. Sozen John E. Breen Neil M. Hawkins John A. Martin, Jr. Dean E. Stephan Anthony P. Chrest C. Raymond Hays Leslie D. Martin Richard A. Vognild* W. Gene Corley Richard E. Holguin Robert F. Mast Joel S. Weinstein Robert A. Epifano Phillip J. Iverson Robert McCluer James K. Wight Catherine W. French James O. Jirsa Richard C. Meininger Loring A. Wyllie, Jr. Luis E. Garcia Gary J. Klein Voting Subcommittee Members Ronald A. Cook Terence C. Holland Gerard J. McGuire Julio A. Ramirez Stephen J. Seguirant Richard W. Furlong Kenneth C. Hover Peter P. M. Meza Gajanan M. Sabnis* Roberto Stark William L. Gamble Michael E. Kreger Denis Mitchell John R. Salmons Maher K. Tadros Roger Green LeRoy A. Lutz Suzanne D. Nakaki David H. Sanders John W. Wallace Scott A. Greer Joe Maffei Randall W. Poston Thomas C. Schaeffer Sharon L. Wood D. Kirk Harman Steven L. McCabe Consulting Members Richard D. Gaynor Edward S. Hoffman Richard A. Ramsey Jacob S. Grossman Francis J. Jacques† Irwin J. Speyer John M. Hanson Alan H. Mattock *Retired from committee before the final ballot. †Deceased. 318/318R-2 ACI STANDARD/COMMITTEE REPORT INTRODUCTION 318/318R-1 BUILDING CODE REQUIREMENTS FOR STRUCTURAL CONCRETE (ACI 318-02) AND COMMENTARY (ACI 318R-02) REPORTED BY ACI COMMITTEE 318 The code portion of this document covers the proper design and construction of buildings of structural concrete. The code has been written in such form that it may be adopted by reference in a general building code and earlier editions have been widely used in this manner. Among the subjects covered are: drawings and specifications; inspection; materials; durability requirements; concrete quality, mixing, and placing; formwork; embedded pipes; construction joints; reinforcement details; analysis and de- sign; strength and serviceability; flexural and axial loads; shear and torsion; development and splices of reinforcement; slab systems; walls; footings; precast concrete; composite flexural members; prestressed concrete; shells and folded plate members; strength evaluation of existing structures; special provisions for seismic design; structural plain concrete; strut-and-tie modeling in Appendix A; alternative design provisions in Appendix B; alternative load and strength-reduc- tion factors in Appendix C; and anchoring to concrete in Appendix D. The quality and testing of materials used in construction are covered by reference to the appropriate ASTM standard specifications. Welding of reinforcement is covered by reference to the appropriate ANSI/AWS standard. Because the ACI Building Code is written as a legal document so that it may be adopted by reference in a general build- ing code, it cannot present background details or suggestions for carrying out its requirements or intent. It is the function of this commentary to fill this need. The commentary discusses some of the considerations of the committee in developing the code with emphasis given to the explanation of new or revised provisions that may be unfamiliar to code users. References to much of the research data referred to in preparing the code are cited for the user desiring to study indi- vidual questions in greater detail. Other documents that provide suggestions for carrying out the requirements of the code are also cited. Keywords: admixtures; aggregates; anchorage (structural); beam-column frame; beams (supports); building codes; cements; cold weather construction; col- umns (supports); combined stress; composite construction (concrete and steel); composite construction (concrete to concrete); compressive strength; concrete construction; concretes; concrete slabs; construction joints; continuity (structural); contraction joints; cover; curing; deep beams; deflections; drawings; earth- quake resistant structures; embedded service ducts; flexural strength; floors; folded plates; footings; formwork (construction); frames; hot weather construction; inspection; isolation joints; joints (junctions); joists; lightweight concretes; loads (forces); load tests (structural); materials; mixing; mix proportioning; modulus of elasticity; moments; pipe columns; pipes (tubing); placing; plain concrete; precast concrete; prestressed concrete; prestressing steels; quality control; rein- forced concrete; reinforcing steels; roofs; serviceability; shear strength; shearwalls; shells (structural forms); spans; specifications; splicing; strength; strength analysis; stresses; structural analysis; structural concrete; structural design; structural integrity; T-beams; torsion; walls; water; welded wire fabric. ACI 318-02 was adopted as a standard of the American Concrete Institute any loss or damage arising therefrom. Reference to this commentary shall not November 1, 2001 to supersede ACI 318-99 in accordance with the Insti- be made in contract documents. If items found in this Commentary are de- tute’s standardization procedure. sired by the Architect/Engineer to be a part of the contract documents, they A complete metric companion to ACI 318/318R has been developed, shall be restated in mandatory language for incorporation by the Architect/ 318M/318RM; therefore no metric equivalents are included in this document. Engineer. ACI Committee Reports, Guides, Standard Practices, and Commentaries Copyright Ó 2002, American Concrete Institute. are intended for guidance in planning, designing, executing, and inspecting All rights reserved including rights of reproduction and use in any form construction. This Commentary is intended for the use of individuals who or by any means, including the making of copies by any photo process, or are competent to evaluate the significance and limitations of its content and by any electronic or mechanical device, printed or written or oral, or record- recommendations and who will accept responsibility for the application of ing for sound or visual reproduction or for use in any knowledge or retrieval the material it contains. The American Concrete Institute disclaims any and system or device, unless permission in writing is obtained from the copy- all responsibility for the stated principles. The Institute shall not be liable for right proprietors. ACI 318 Building Code and Commentary 318/318R-2 INTRODUCTION The 2002 ACI Building Code and Commentary are presented in a side-by-side column format, with code text placed in the left column and the corresponding commentary text aligned in the right column. To further distin- guish the Code from the Commentary, the Code has been printed in Helvetica, the same type face in which this paragraph is set. Vertical lines in the margins indicate changes from ACI 318-99, including nontechnical changes such as a new section or equation number. 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. Vertical lines in the margins indicate changes from ACI 318R-99, including nontechnical changes such as a new section or equation number. INTRODUCTION The commentary directs attention to other documents that provide suggestions for carrying out the requirements and in- This commentary discusses some of the considerations of tent of the code. However, those documents and the com- Committee 318 in developing the provisions contained in mentary are not a part of the code. “Building Code Requirements for Structural Concrete (ACI 318-02),” hereinafter called the code or the 2002 code. Em- The code has no legal status unless it is adopted by the gov- phasis is given to the explanation of new or revised provi- ernment bodies having the police power to regulate building sions that may be unfamiliar to code users. In addition, design and construction. Where the code has not been adopt- comments are included for some items contained in previous ed, it may serve as a reference to good practice even though editions of the code to make the present commentary inde- it has no legal status. pendent of the commentary for ACI 318-99. Comments on specific provisions are made under the corresponding chap- The code provides a means of establishing minimum standards ter and section numbers of the code. for acceptance of designs and construction by a legally ap- pointed building official or his designated representatives. The The commentary is not intended to provide a complete his- code and commentary are not intended for use in settling dis- torical background concerning the development of the ACI putes between the owner, engineer, architect, contractor, or * Building Code, nor is it intended to provide a detailed ré- their agents, subcontractors, material suppliers, or testing agen- sumé of the studies and research data reviewed by the com- cies. Therefore, the code cannot define the contract responsibil- mittee in formulating the provisions of the code. However, ity of each of the parties in usual construction. General references to some of the research data are provided for those references requiring compliance with the code in the job spec- who wish to study the background