Estimation of Accidental Torsion Effects for Seismic Design of Buildings
Publication: Journal of Structural Engineering
Volume 121, Issue 1
Abstract
A procedure is developed for including the effects of accidental torsion in seismic design of buildings. It has four steps. First, the ratio between the fundamental frequencies of uncoupled torsional and lateral motions of the building is computed. This ratio and plan dimensions are then used to estimate the increase in displacements at the edge of the building resulting from all sources of accidental torsion. Third, from these edge displacements the increase in displacements at the location of interior resisting planes are estimated. Finally, the design forces in structural members are computed by amplifying the forces ignoring accidental torsion by the increase in building displacements determined previously. This procedure has several advantages over the code-specified static and dynamic analysis procedures to include accidental torsion, such as: (1) The elimination of cumbersome static or three-dimensional dynamic analyses to account for accidental torsion effects in building design; and (2) the inclusion of the effects of all sources of accidental torsion. Two building examples are presented to illustrate these advantages as well as the computational steps required to implement the new procedure.
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References
1.
De la Llera, J. C., and Chopra, A. K. (1994a). “Accidental torsion in buildings.”Proc., 6th U.S. Nat. Conf. in Earthquake Engrg., Vol. II, 401–410.
2.
De la Llera, J. C., and Chopra, A. K.(1994b). “Accidental-torsion in buildings due to stiffness uncertainty.”Earthquake Engrg. and Struct. Dynamics, 23(2), 117–136.
3.
De la Llera, J. C., and Chopra, A. K.(1994c). “Accidental-torsion in buildings due to base rotational excitation.”Earthquake Engrg. and Struct. Dynamics, 23(9), 1003–1021.
4.
De la Llera, J. C., and Chopra, A. K.(1994d). “Evaluation of code accidental-torsion provisions from building records.”J. Struct. Engrg., ASCE, 120(2), 597–616.
5.
De la Llera, J. C., and Chopra, A. K.(1994e). “Using accidental eccentricity in code-specified static and dynamic analyses of buildings.”Earthquake Engrg. and Struct. Dynamics, 23(9), 947–967.
6.
Dempsey, K. M., and Tso, W. K. (1982). “An alternative path to seismic torsional provisions.”Soil Dynamics and Earthquake Engrg., 1(1), 3–10.
7.
Earthquake resistant regulations, a world list. (1988). International Association for Earthquake Engineering, Tokyo, Japan.
8.
Hejal, R., and Chopra, A. K. (1989). “Response spectrum analysis of class of torsionally coupled buildings.”J. Engrg. Mech., ASCE, 115(8), 1761–1781.
9.
National building code of Canada. (1985). Associate Committee on the National Building Code, National Research Council of Canada, Ottawa, Ontario.
10.
Newmark, N. M. (1969). “Torsion in symmetrical buildings.”Proc., 4th World Conf. in Earthquake Engrg., A3, Santiago, Chile, 19–32.
11.
Riddell, R., and Vásquez, J. (1984). “Existence of centers of resistance and torsional uncoupling of earthquake response of buildings.”Proc., 8th World Conf. in Earthquake Engrg., Prentice-Hall, Inc., Englewood Cliffs, N.J., Vol. IV, 187–194.
12.
Tso, W. K., and Cheung, W. T. (1986). “Decoupling of equations of equilibrium in lateral load analysis of multistory buildings.”Computers and struct., 23(5), 679–684.
13.
Uniform building code. (1991). Int. Conf. of Build. Officials, Whittier, Calif.
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Copyright © 1995 American Society of Civil Engineers.
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Published online: Jan 1, 1995
Published in print: Jan 1995
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