Three-Dimensional Static and Dynamic Analysis of Structures
(5YM?QAd A Physical Approach With Emphasis on Earthquake Engineering
^{`exCwM x Z5n1@a __ by
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M Edward L. Wilson
9.-S( ZO Professor Emeritus of Structural Engineering
5C ]x!>kX University of California at Berkeley
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#0,p Copyright Computers and Structures, Inc., 1996-2001
9 cF[seE"0 The CSI Logo is a trademark of Computers and Structures, Inc.
H*R"ntI?w SAP90, SAP2000, SAFE, FLOOR and ETABS are trademarks of
@Nx 9) Computers and Structures, Inc.
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ISBN 0-923907-00-9
cuI TY^6 uGG t\.$]s Preface To Third Edition
KV *#T2 0T This edition of the book contains corrections and additions to the July 1998 edition.
.`eN8Dl1 Most of the new material that has been added is in response to questions and comments
mq.`X:e from the users of SAP2000, ETABS and SAFE.
Btn?N Chapter 22 has been written on the direct use of absolute earthquake displacement
0s[Hkhls loading acting at the base of the structure. Several new types of numerical errors for
bAqA1y3= absolute displacement loading have been identified. First, the fundamental nature of
{JT&w6Jz displacement loading is significantly different from the base acceleration loading
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traditionally used in earthquake engineering. Second, a smaller integration time step is
7JH6A'& required to define the earthquake displacement and to solve the dynamic equilibrium
2/^3WY1U equations. Third, a large number of modes are required for absolute displacement
qEOhwrh loading to obtain the same accuracy as produced when base acceleration is used as the
b8UO,fY q loading. Fourth, the 90 percent mass participation rule, intended to assure accuracy of
\M^bD4';> the analysis, does not apply for absolute displacement loading. Finally, the effective
*i%d,w0+ modal damping for displacement loading is larger than when acceleration loading is
03Ycf'W used.
C&%_a~ To reduce those errors associated with displacement loading, a higher order integration
g3y ~bf method based on a cubic variation of loads within a time step is introduced in Chapter
U i W > J 13. In addition, static and dynamic participation factors have been defined that allow the
{!L~@r structural engineer to minimize the errors associated with displacement type loading. In
W ac&b addition, Chapter 19 on viscous damping has been expanded to illustrate the physical
Q)h(nbbVak effects of modal damping on the results of a dynamic analysis.
KZE,bi: ~ Appendix H, on the speed of modern personal computers, has been updated. It is now
#;yZ possible to purchase a personal computer for approximately $1,500 that is 25 times
wP@(?z faster than a $10,000,000 CRAY computer produced in 1974.
1))8
A@, Several other additions and modifications have been made in this printing. Please send
6bC3O4Rw your comments and questions to
ed@csiberkeley.com.
Ti5-6%~& Edward L. Wilson
_G@GpkSe> April 2000
