Three-Dimensional Static and Dynamic Analysis of Structures
{9;CNsd A Physical Approach With Emphasis on Earthquake Engineering
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}mq6]ZrK by
-)]Yr #Q Edward L. Wilson
dIa+K?INX Professor Emeritus of Structural Engineering
e~[/i\ University of California at Berkeley
Bsq P?/ L M bn Copyright Computers and Structures, Inc., 1996-2001
(X1e5j>Ru The CSI Logo is a trademark of Computers and Structures, Inc.
1;r|g)VM SAP90, SAP2000, SAFE, FLOOR and ETABS are trademarks of
q #ClnG* Computers and Structures, Inc.
[-k ISBN 0-923907-00-9
Ou!2 [oe@M m^f0V2M_ Preface To Third Edition
X0H!/SlS This edition of the book contains corrections and additions to the July 1998 edition.
(%e .:W${ Most of the new material that has been added is in response to questions and comments
{V$|3m>:* from the users of SAP2000, ETABS and SAFE.
T?soJ]A Chapter 22 has been written on the direct use of absolute earthquake displacement
D4-ifs P loading acting at the base of the structure. Several new types of numerical errors for
E=CsIK absolute displacement loading have been identified. First, the fundamental nature of
JG!m c7 displacement loading is significantly different from the base acceleration loading
E +R1 !. traditionally used in earthquake engineering. Second, a smaller integration time step is
`maKN \; required to define the earthquake displacement and to solve the dynamic equilibrium
q`H_M{26!y equations. Third, a large number of modes are required for absolute displacement
,+vy,<e& loading to obtain the same accuracy as produced when base acceleration is used as the
i6tf2oqO7 loading. Fourth, the 90 percent mass participation rule, intended to assure accuracy of
zrL$]Oy}x the analysis, does not apply for absolute displacement loading. Finally, the effective
ith
3 =`3 modal damping for displacement loading is larger than when acceleration loading is
w/S%YW3* used.
K&Z tRRDd To reduce those errors associated with displacement loading, a higher order integration
[OV"}<V method based on a cubic variation of loads within a time step is introduced in Chapter
.4M.y:F 13. In addition, static and dynamic participation factors have been defined that allow the
%.Fi4}+ O structural engineer to minimize the errors associated with displacement type loading. In
eH3JyzzP, addition, Chapter 19 on viscous damping has been expanded to illustrate the physical
q?oP ?cCw effects of modal damping on the results of a dynamic analysis.
&5spTMw8 Appendix H, on the speed of modern personal computers, has been updated. It is now
w QH<gJE/: possible to purchase a personal computer for approximately $1,500 that is 25 times
NI}yVV faster than a $10,000,000 CRAY computer produced in 1974.
z/W E,R Several other additions and modifications have been made in this printing. Please send
st3l2Q your comments and questions to
ed@csiberkeley.com.
[.'| _l Edward L. Wilson
EZy)A$| April 2000
