Influence of the interaction yield domain on lateral-torsional coupling of asymmetric single-storey systems

Single-storey models are widely adopted because they are able to describe the main aspects of the torsional coupling of asymmetric buildings and, at the same time, they are simple enough to enable extensive parametric analysis. Generally, single-story systems are constituted by a rigid deck, where the mass is lumped, supported by vertical resisting elements with lateral stiffness and strength in their plane only (uni-axial resisting elements). Thus, these models neglect the interaction phenomena that can be observed in actual framed structures, where the vertical resisting elements provide lateral stiffness and strength in all the horizontal directions. In this chapter, the influence of the interaction phenomena on the torsional coupling of the seismic response of asymmetric buildings predicted by nonlinear methods of analysis is investigated. Single storey systems with bi- and uni-axial resisting elements are used to simulate structures whose seismic response is affected or not by interaction phenomena. Finally, both nonlinear dynamic and nonlinear static methods of analysis are investigated.