Structural Design Guide to the ACI Building Code
Paul F. Rice & Edward S. Hoffman
Van Nostrand Reinhold, 1979
x + 470 Hal.
Rp. 53,000 ,- (Sudah Terjual)
This book is intended to guide practicing structural engineers familiar with earlier ACI building codes into more profitable routine designs with the ACI 1977 Building Code (ACI 318-77).
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 utilization of high-strength reinforcement and the compressive strength of the concrete itself. Each new code thus permitted more economy as to construction material, but achieved it through more detailed and complicated design calculations. In addition to competition requiring independent structural engineers to follow the latest code for economy, the reduction of shear and bond values from those previously allowed created a professional obligation to follow 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. Computer time and development of such new computer design programs are costly, however, and computers are not available to all engineers. Also, it is not economical to program all design problems encountered.
This book will guide the user to the various sections of the Code pertinent to design of common reinforced concrete structural elements. A brief explanation of the significance of these sections is presented, together with limits of applicability, the range in which results may control design; and, where possible, design short cuts to insure automatic conformance to the Code without calculations.
This Guide does not duplicate nor replace the ACI Code, its Commentary, design handbooks, or use of computers. It complements the ACI Code and Commentary, shows how to take full advantage of available handbooks based on ’63 to ’77 Codes, and should shorten time to develop computer design programs. It converts some code formulas from the review form (or trial designs) to direct design. It presents some simple appropriate formulas, tabulations, and charts for conservative longhand direct design.
Specifications for materials and special Code requirements superimposed upon the ASTM Specifications for materials are explained to aid the structural engineer to avoid difficulties with use of obsolete specifications.
The overall objective of this book is simply to save the Engineer time in reinforced concrete design.
HOW TO USE THIS GUIDE
Code requirements applicable to the design of structural building elements, scattered through various Code chapters, have been assembled for the analysis and design of one-way slabs, one-way joists, beams, the various types of two-way slab systems with and without beams, prestressed flexural members, columns, walls, and footings.
Most of the numerical examples are based on normal weight concrete with fc’ = 4,000 psi for flexural members and 4,000, 5,000, or 6,000 psi for columns; and the standard Grade 60 reinforcement. For lightweight aggregate concrete, see Chapter 15. Other concrete strengths used are so indicated.
Provisions new to the Code are noted as such for especial attention. It is assumed that users of the guide are familiar with reinforced concrete design and structural analysis as well as the terms and symbols in common use. Definitions of new nomenclature and symbols follow this introduction.
This guide is intended for use with the Code itself. Space limitations make it impracticable to include the Code. The Guide indicates the proper sections of the Code in the order that a designer would normally require their use for design of a particular building element. In the appropriate chapter for the element being designed, the Engineer will find the applicable Code sections indicated in parenthesis thus: “(Section 00.00.00)” following the explanations of their application.
Explanations of requirements difficult to interpret are followed by numerical examples. Where several Code equations or requirements are applicable simultaneously and must be solved to determine which controls, computer solutions over the usual range have been included as convenient tables or curves. Where examination of computer solutions over a wide range show simple approximations by longhand possible, such short cuts, together with limitations of range or accuracy are given. For especially difficult or unusual problems outside the scope of this guide, other references are cited to guide the Engineer to a quick source of information for detailed study. References to the ACI Code Commentary are indicated thus: “(Commentary 00.00.00).”
No attempt has been made to explain each individual Section of the Code in this book. A large number of Code provisions which have provoked little or no question of interpretation in past codes have been repeated essentially without change in the 1977 Code.
Other exclusions are precast concrete and composite (precast with cast-in-place concrete) design procedures which involve no separate design theory but merely consideration of different load conditions due to construction sequences. An alternate (working stress) design method is permitted by Appendix B of the Code, but the working stress is uneconomical. The new Code provisions for thin shell and folded-plate design serve only to include these structures within the scope of the Code. Similarly, the provisions for seismic design of special ductile frames in Appendix A are intended to provide generally accepted details of design for use with various regional seismic code requirements. The variety of plates, shells, and seismic details precludes their inclusion here. Any explanation of seismic details here would also of necessity duplicate the report on seismic details by ACI Committee 315* in which both authors participated and recommend.
Two indexes are provided, a subject index and a Code section reference index. The user wishing to locate all Code references to a particular subject, as well as the user interested in the interpretation of a particular Code section, should find this arrangement most convenient.
BUILDING CODE REQUIREMENTS FOR REINFORCED CONCRETE (ACI 318-77)
The 1977 Code revision appears in an almost completely new format. Each separate requirement has been given a separate sub- or sub-sub section number, providing improved clarity and more specific references. Portions of Chapter 7 (Details) particularly those dealing with splices have been relocated in Chapter 12 (Development) to save the user much back-and-forth cross-reference reading. Chapter 11 (Shear) has been rewritten in terms of force (instead of stress) with necessary new notation which facilitates teaching the subject. These format changes are on the whole improvements to facilitate use of the Code.
Substantive revisions in structural application have been held to a bare minimum. For the users’ convenience, these changes may be summarized very succinctly: (1) maximum column load, page 276; (2) two-way shear at rectangular supports, page 366; (3) limiting torsion from indeterminate frame action, page 240; (4) lateral load analysis of two-way slab and column frames, page 29; (5) stress block in compression, )9 1, page 32; and (6) design of brackets and corbels and deep beams, page 368.
Appendixes in the First Edition, 1972, showing then-new notation for Code and Commentary have been eliminated. Code users are now familiar with the 1971 notation, and each notation new to the 1977 Code is defined here as the explanations for it are given.