Building Code Requirements for Structural Concrete and Commentary

APPENDIX E—STEEL REINFORCEMENT INFORMATION .............................................................. 439
APPENDIX F—EQUIVALENCE BETWEEN SI-METRIC, MKS-METRIC, AND U.S. CUSTOMARY 
UNITS OF NONHOMOGENOUS EQUATIONS IN THE CODE ............................................. 441
COMMENTARY REFERENCES .......................................................................................................... 449
INDEX................................................................................................................................................... 467

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INTRODUCTION
7
ACI 318 Building Code and Commentary
INTRODUCTION
This Commentary discusses some of the considerations of
Committee 318 in developing the provisions contained in
“Building Code Requirements for Structural Concrete (ACI
318-08),” hereinafter called the Code or the 2008 Code.
Emphasis is given to the explanation of new or revised
provisions that may be unfamiliar to Code users. In addition,
comments are included for some items contained in previous
editions of the Code to make the present commentary
independent of the previous editions. Comments on specific
provisions are made under the corresponding chapter and
section numbers of the Code.
The Commentary is not intended to provide a complete
historical background concerning the development of the
Code,
*
nor is it intended to provide a detailed résumé of the
studies and research data reviewed by the committee in
formulating the provisions of the Code. However, references
to some of the research data are provided for those who wish
to study the background material in depth.
As the name implies, “Building Code Requirements for
Structural Concrete” is meant to be used as part of a legally
adopted building code and as such must differ in form and
substance from documents that provide detailed specifications,
recommended practice, complete design procedures, or
design aids.
The Code is intended to cover all buildings of the usual
types, both large and small. Requirements more stringent
than the Code provisions may be desirable for unusual
construction. The Code and Commentary cannot replace
sound engineering knowledge, experience, and judgment.
A building code states only the minimum requirements
necessary to provide for public health and safety. The Code
is based on this principle. For any structure, the owner or the
licensed design professional may require the quality of
materials and construction to be higher than the minimum
requirements necessary to protect the public as stated in the
Code. However, lower standards are not permitted.
The Commentary directs attention to other documents that
provide suggestions for carrying out the requirements and
intent of the Code. However, those documents and the
Commentary are not a part of the Code.
The Code has no legal status unless it is adopted by the
government bodies having the police power to regulate
building design and construction. Where the Code has not
been adopted, it may serve as a reference to good practice
even though it has no legal status.
The Code provides a means of establishing minimum standards
for acceptance of designs and construction by legally
appointed building officials or their designated representatives.
The Code and Commentary are not intended for use in settling
disputes between the owner, engineer, architect, contractor, or
their agents, subcontractors, material suppliers, or testing
agencies. Therefore, the Code cannot define the contract
responsibility of each of the parties in usual construction.
General references requiring compliance with the Code in the
project specifications should be avoided since the contractor is
rarely in a position to accept responsibility for design details or
construction requirements that depend on a detailed knowledge
of the design. Design-build construction contractors, however,
typically combine the design and construction responsibility.
Generally, the drawings, specifications, and contract documents
should contain all of the necessary requirements to ensure
compliance with the Code. In part, this can be accomplished
by reference to specific Code sections in the project specifi-
cations. Other ACI publications, such as “Specifications for
Structural Concrete (ACI 301)” are written specifically for
use as contract documents for construction.
It is recommended to have testing and certification programs
for the individual parties involved with the execution of
work performed in accordance with this Code. Available for
this purpose are the plant certification programs of the
Precast/Prestressed Concrete Institute, the Post-Tensioning
Institute, and the National Ready Mixed Concrete Associa-
tion; the personnel certification programs of the American
Concrete Institute and the Post-Tensioning Institute; and the
Concrete Reinforcing Steel Institute’s Voluntary Certification
The ACI Building Code Requirements for Structural Concrete (“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 distinguish the Code from the Commentary, the Code has been printed in Helvetica, the same type face in which
this paragraph is set.
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.
Except for Chapters 4 and 21, substantive changes from 318-05 are indicated with vertical lines in the margin (editorial
changes not indicated). Changes to the provisions of Chapters 4 and 21 are not indicated by a vertical line because the
provisions were renumbered for this edition.
*
For a history of the ACI Building Code see Kerekes, F., and Reid, H. B., Jr., “Fifty
Years of Development in Building Code Requirements for Reinforced Concrete,” ACI
J
OURNAL
, Proceedings V. 50, No. 6, Feb. 1954, p. 441. For a discussion of code philos-
ophy, see Siess, C. P., “Research, Building Codes, and Engineering Practice,” ACI
J
OURNAL
, Proceedings V. 56, No. 5, May 1960, p. 1105.

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