The publication of this fourth edition reflects the continuing change occurring in design procedures relating to reinforced concrete structures. The strength design philosophy is now well established. Current design recognizes that the “Ú.mit of usefulness” or “limit state” is reached when the strength of the member is fully utilized, or it may be reached when the member is no longer serviceable (such as when it deflects too much). Either strength or serviceability may control the design and provision must be
made for both.
The fourth edition reflects the changes in design rules arising from the publication- of the 1983 American Concrete Institute (ACI) Building Code and Commentary. Changes in the 1983 ACI Code include those appearing in the 1980 Supplement as well as those approved by ACI Committee 318 (Standard Building Code) since 1980.