Seismic Demand of Low-Rise Multistory Systems with General Asymmetry.

This study examined the inelastic seismic behavior of low-rise systems with varying story eccentricities (i.e., general class of eccentric systems). Seismic demands of such systems were found to be potentially high relative to those obtained from single-story or regularly asymmetric models, particularly for flexible-side elements of torsionally stiff systems and stiff-side elements of torsionally flexible systems. This appears to be a consequence of the complex participation of higher torsion-dominated modes in multistory systems with general class of asymmetry, unlike the predominant participation of single torsional mode in its regularly asymmetric counterpart. The study also indicates that the degrading features of RC structural elements may cause a significant increase in inelastic demands. Summarizing elastic range response, coefficients α and δ are proposed to predict seismic demand through equivalent static analysis. Further, a design envelope was outlined to predict inelastic seismic demand. This may prove useful in the selection of the appropriate response reduction factor in practical design. Observations highlighting the dynamics of multistory systems with generalized asymmetry establish the conceptual framework for envisioning the seismic response. [ABSTRACT FROM AUTHOR]