The Earthquake Engineering Online Archive

Linear and nonlinear earthquake responses of simple torsionally coupled systems

Kan, Christopher L.; Chopra, Anil K.

UCB/EERC-79/03, Earthquake Engineering Research Center, University of California, Berkeley, 1979-02, 120 pages (555.5/K218/1979)

The effects of torsional coupling on the earthquake response of simple single-story structures in both the elastic and inelastic ranges of behavior are analyzed. The structures considered are symmetrical about one principal axis of resistance, resulting in coupling only between lateral displacement along the perpendicular principal axis and the torsional displacement. Torsional coupling arising only from eccentricity between centers of mass and elastic resistance is considered. Systems with several resisting elements, columns, and walls are idealized by a single-element model. Responses of such a model to a selected earthquake ground motion are presented for a wide range of the basic structural parameters. The results presented include maximum lateral and torsional deformations of the system as well as maximum deformations of individual columns. It is shown that the inelastic response is affected by torsional coupling to generally a lesser degree than elastic response. Procedures are presented for estimating, to a useful degree of approximation, the maximum responses of elastic and inelastic systems from the corresponding response spectra and the maximum deformations of individual columns from the displacements at the center of mass.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-79-03.pdf (6 MB)