This book is intended to guide practicing structural engineers familiar with ear­ lier ACI building codes into more profitable routine designs with the ACI 1995 Building Code (ACI 318-95). Each new ACI Building Code expresses the latest knowledge of reinforced concrete in legal language for safe design application. Beginning in 1956 with the introduction of ultimate strength design, each new code offered better uti­ lization of high-strength reinforcement and the compressive strength of the con­ crete itself. Each new code thus permitted more economy as to construction material, but achieved it through more detailed and complicated design calcula­ tions. In addition to competition requiring independent structural engineers to follow the latest code for economy, it created a professional obligation to fol­ low the latest code for accepted levels of structural safety. The increasing complexity of codes has encouraged the use of computers for design and has stimulated the development of computer-based handbooks. Before computer software can be successfully used in the structural design of buildings, preliminary sizes of structural elements must be established from handbook tables, estimates, or experienced first guesses for input into the com­ puter.