Effects of torsion on the behaviour of non-structural components mounted on irregular reinforced concrete multi-storey buildings

Abstract

This paper considers the seismic responses of acceleration-sensitive non-structural components (NSCs) attached to irregular multi-storey reinforced concrete (RC) structures using Finite Element (FE) approach. The main objective of this study is to evaluate the behaviour of NSCs mounted on irregular RC buildings due to the effects of structural ductility and torsion which take place during earthquakes. Nonlinear dynamic analyses were used to evaluate the seismic behaviour of primary-secondary systems. The P-structures in this study include five irregular RC buildings which have the same asymmetric plan configuration, while having different number of stories, i.e., 5, 7, 10, 13, and 15-storeys. The P-structures were designed by the authors according to the full seismic provisions of Eurocode 8 (EC8). Distributed inelastic fibre elements are adopted to model the beams and columns of the P-structures. To simulate NSCs in P-structures, vertical cantilever beams fixed at their bases with masses on top are modelled with variety of lengths to adjust their natural frequencies to the natural frequencies of the P-structures. Full dynamic interaction is considered between the NSCs and P-structures during the analyses. A comparison is made between the numerical results and the EC8 formulation, and a general conclusion is drawn that the provisions of EC8 for design of NSCs are un-conservative in some cases.