Maximum Corner Displacement Amplifications for Inelastic One-Storey In-Plan Asymmetric Systems Under Seismic Excitation

Abstract

The seismic behaviour of one-storey asymmetric structures has been extensively studied since 1970s by a number of research studies which identified the coupled nature of the translational-to-torsional response of this class of systems leading to severe displacement magnifications at the perimeter frames and to significant increase of local peak seismic demand to the structural elements. In previous research works, some of the authors introduced a simplified method, the so called “Alpha” method, for the estimation of the maximum torsional response of linear-elastic one-storey in-plan asymmetric systems. The present paper provides an extension of the “Alpha” method to inelastic systems. The main objective is to evaluate how the excursion of the structural elements in the inelastic range affects the seismic displacement demand. In detail, 3-D surfaces of corner displacement magnification factors for different force reduction factors are showed and comparisons with the results obtained from linear analysis are provided. The 3-D surfaces could be useful to assess the seismic displacement demand of asymmetric systems in a preliminary design phase.