Torsional Response of Unsymmetric Buildings to Incoherent Ground Motions
Publication: Journal of Structural Engineering
Volume 120, Issue 4
Abstract
The behavior of unsymmetric buildings excited by incoherent seismic ground motions is studied, and the assessments and information reported make it possible to gain valuable insight into the resulting dynamic response. The effects of the ground motion incoherence and of the structural eccentricity are first considered independently of one another, and attempts are made to identify their relative importance. The torsional effects induced by the incoherence actions are interpreted in terms of normalized accidental eccentricities; and comparisons are made of these eccentricities with the value of 0.05 specified by design codes. Such comparisons form a frame of reference for the assessment of the importance of the torsional effects resulting from the ground motion incoherence. The coupled effects of incoherence and eccentricity are then considered, and it is reported that they can be approximately represented by proper combinations of the corresponding independent effects, under conditions that are of practical importance. This approximation leads to the definition of effective modified eccentricities, which can be useful for the appreciation of the torsional effects induced in building structures by earthquakes.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Abrahamson, N. A., and Bolt, B. A. (1985). “The spatial variation of the phasing of seismic strong ground motion.” Bull. of the Seismological Society of America, 75(5).
2.
Applied Technological Council (ATC). (1978). Tentative provisions for the development of seismic regulations for buildings. ATC3‐06, Palo Alto, Calif.
3.
Chandler, A. M., and Hutchinson, G. L. (1987). “Evaluation of code torsional provisions by a time history approach.” J. Earthquake Engrg. and Struct. Dynamics, 15, 491–516.
4.
Chopra, A. K., and Goel, R. K. (1991). “Evaluation of torsional provisions in seismic codes.” J. Struct. Engrg., ASCE, 117(12), 3762–3782.
5.
Clough, R. W., and Penzien, J. (1993). Dynamics of structures. 2d Ed., McGraw‐Hill, New York, N.Y.
6.
Der Kiureghian, A. (1980). “Structural response to stationary excitation.” J. Engrg. Mech., ASCE, 106(6), 1195–1213.
7.
Harichandran, R. S., and Vanmarcke, E. H. (1986). “Stochastic variation of earthquake ground motion in space and time.” J. Engrg. Mech., ASCE, 112(2), 154–174.
8.
Hejal, R., and Chopra, A. K. (1989a). “Earthquake response of torsionally coupled, frame buildings.” J. of Struct. Engrg., ASCE, 115(4), 834–851.
9.
Hejal, R., and Chopra, A. K. (1989b). “Lateral‐torsional coupling in earthquake response of frame buildings.” J. Struct. Engrg., ASCE, 115(4), 852–867.
10.
Iguchi, M. (1982). “An approximate analysis of input motions for rigid embedded foundations.” Trans. Architectural Inst. of Japan, 315, May, 61–73.
11.
Kausel, E., and Pais, A. (1985). “Stochastic response of foundations.” Res. Report R85‐6, Dept. of Civ. Engrg., Massachusetts Inst. of Tech., Cambridge, Mass.
12.
Loh, C. H., and Penzien, J. (1984). “Identification of wave‐types, directions, and velocities using SMART‐1 strong motion array data.” Proc., 8th World Conf. on Earthquake Engrg., San Francisco, Calif., Vol. 2, 191–198.
13.
Luco, J. E., and Mita, A. (1987). “Response of circular foundation to spatially random ground motion.” J. of Engrg. Mech., ASCE, 113(1), Jan. 1–15.
14.
Luco, J. E., and Sotiropoulos, D. A. (1980). “Local characterization of free‐field ground motion and effects of wave passage.” Bulletin Seismological Society of America, 70(6), 2229–2244.
15.
Luco, J. E., and Wong, H. L. (1986). “Response of a rigid foundation to a spatially random ground motion.” J. Earthquake Engrg. and Struct. Dynamics, 14, 891–908.
16.
Morgan, J. R., Hall, W. J., and Newmark, N. M. (1983). “Seismic response arising from traveling waves.” J. Struct. Engrg., 109(4), 1010–1027.
17.
Newmark, N. M. (1969). “Torsion in symmetrical buildings.” Proc., 4th World Conf. on Earthquake Engrg., Santiago, Chile, Vol. 2, 19–32.
18.
Scanlan, R. H. (1976). “Seismic wave effects on soil‐structure interaction.” J. Earthquake Engrg. and Struct. Dynamics, 4, 379–388.
19.
Uniform Building Code (UBC). (1988). International Conf. of Building Officials, Whittier, Calif.
20.
Veletsos, A. S., and Prasad, A. M. (1989). “Seismic interaction of structures and soils: stochastic approach.” J. Struct. Engrg., 115(4), 935–956.
Information & Authors
Information
Published In
Copyright
Copyright © 1994 American Society of Civil Engineers.
History
Received: May 4, 1993
Published online: Apr 1, 1994
Published in print: Apr 1994
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.