Inelastic parametric analysis of two-way asymmetrical multi-storey buildings

Abstract

This article presents a parametric study on the lateral-torsional coupling behaviour of the simplified bidirectional asymmetric multi-storey dual lateral load-resisting model. The implementation process for establishing the simplification model is shown in an illustrative example on a three-storey reinforced concrete building system. Combined with the force–displacement relationships of the lateral load-resisting members and the inter-story restoring force models, the dynamic stiffness matrix and the equations of motion under different loading conditions can also be determined. On this basis, parametric analyses for the systems are carried out through the whole loading process from the elastic stage to the inelastic stage. Effects of uncoupled torsion to lateral frequency ratios (Ω) and the stiffness eccentricities on the frequencies are investigated. The analysis shows that the asymmetrical system with a smaller Ω value has a smaller torsional stiffness and a stronger lateral-torsional coupling effect. The effects of the eccentricities in both directions on the frequencies are remarkably different. Smaller Ω values and greater eccentricities lead to greater reductions in the effects of Ω and eccentricities on the frequencies in the inelastic stage.