Identification of Torsionally Stiff and Flexible Asymmetric Systems, and Their Comparative Seismic Response Evaluation for Low-Rise Frames

ABSTRACT

Torsional status indicators of asymmetrical plan systems are evaluated. The ratio of two modal participation factors in a translational direction (lower to higher mode) is proved as a more accurate indicator than the ratio of translation and rotation dominant modal periods. Seismic responses of low-rise asymmetric-plan frames are then assessed through linear elastic and nonlinear response analysis of representative systems under bi-axial ground motion pairs. The results revealed that those systems that are initially identified as torsionally stiff exhibit a torsionally stiff nonlinear response, whereas those initially categorized as torsionally balanced or flexible evolve to a stiffer torsional performance.

KEYWORDS:

• Asymmetric systems
• plan irregularity
• torsional status indicators
• torsionally stiff
• torsionally flexible
• accidental eccentricity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available on request from the authors.