Nonlinear Response of Torsionally Coupled Structures

Abstract

<p>Very little research has been done on the nonlinear response of asymmetric structures although real buildings may undergo plastic deformations in response to strong ground excitation. Also, it is a common design philosophy to permit inelastic behaviour since lower design forces may be, used.</p> <p>In this analysis, the nonlinear response of a torsionally coupled single-story model consisting of a rigid diaghram resting on three equally spaced frames is investigated. The main concern herein is the peak ductility demand especially at edges.</p> <p>A limited parametric study is undertaken to identify trends in peak ductility demand. The effects of torsional coupling in nonlinear systems are also investigated. Real earthquake records as well as an idealized sinusoidal excitation are used as ground motion. Two types of load-deformation relation are used: (1) the simple bilinear type which can adequately simulate the dynamic response of steel structural elements, (ii) the Clough's degrading stiffness model to simulate the hysteretic behaviour of reinforced concrete structural elements. A comparison between both types is made to assess the significance of the type of load-deformation relation.</p>