EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, VOL. 24, 1173 (1995)

BOOK REVIEW

DYNAMICS OF STRUCTURES: THEORY AND APPLICATIONS TO EARTHQUAKE ENGINEERING, by Anil K. Chopra, Prentice-Hall, Englewood Cliffs, NJ, 1995. No. of pages: xxviii + 761, ISBN 0-13-855214-2.

This is an important book which will be of interest to all readers of this Journal. The author is an internationally recognized expert in the field of earthquake engineering and structural dynamics who has had not only an im- pressive record in research and practice, but also much experience in the classroom. The book will thus be valu- able for the student, and for practising engineers who will find much information on recent developments in the analysis of the effects of earthquakes on structures.

The level of the present book is that of the senior undergraduate and first-year graduate student. Although the book is organized as a textbook, it is particularly well suited to self-study because of the detailed explanations of basic principles, and because of the many completely worked out numerical illustrative examples. An impor- tant feature of the book is the many excellent diagrams. These diagrams are for the most part computer-gener- ated, and are very clear and accurate.

The first part of the book, in some 310 pages, is devoted to a detailed study of single-degree-of-freedom systems. Notable in this section is the extensive treatment of step and pulse excitations, the response of inelastic systems, and the numerical solution of dynamic response problems. The treatment is characterized by a very care- ful discussion of basic principles, and an emphasis on the physical interpretation of results.

The second part of the book, in some 328 pages, considers multi-degree-of-freedom systems. Normal mode theory is carefully developed, with applications to ground-excited structures, including such details as mul- tiple support systems, non-classically damped systems and torsional response. A detailed investigation of modal response contributions in multi-degree-of-freedom sys- tems shows how such modal contributions are influenced

by spatial distribution and time variation of exciting forces. Practical criteria are given as to the number of modes to include in response calculations, and as to how to combine modes in response spectrum calculations. A chapter on damping in structures summarizes much practical information on this important subject.

The last section of the book, in some 90 pages, applies the preceding theory to practical problems of the earth- quake response and design of multi-storey buildings. These chapters contain much new information hitherto available only in specialized research publications. The parameter beam-to-column stiffness ratio is introduced, and it is shown that much general information on vibra- tion periods in structures can be revealed through its use. Various trends in distribution of modal periods and the influence on response are developed, and practical in- formation on the number of modes to include in dynamic analysis is given. An especially important chapter on the earthquake response of inelastic buildings is included, with informative details on allowable ductility and duc- tility demand. A chapter on base-isolated structures is timely, with a discussion of the effectiveness of base isolation and of the conditions under which such measures may be appropriate. The concluding chapter is an illuminating discussion of the way in which structural dynamics theory is introduced into typical building codes, along with a critical evaluation of some existing codes.

The many readers of Professor Chopra’s very popular book Dynamics of Structures, a Primer, issued as a mono- graph of the Earthquake Engineering Research Institute in 1980, will be pleased to find that the present volume will be well suited to extending and deepening their knowledge in this subject. This new book is a most welcome addition to the literature of the subject, and will no doubt take a permanent place in that literature.

DONALD E. HUDSON Pasadena, C A