Incremental dynamic analysis of steel frames equipped with NiTi shape memory alloy braces

Abstract

This paper determines the seismic performance of four-storey concentrically braced frames equipped with either steel buckling-restrained braces or buckling-restrained superelastic shape memory alloy (SMA) braces through incremental dynamic analysis. The incremental dynamic analysis technique is used to examine the behaviour of four-storey braced frames with four different bracing configurations (including diagonal, split-X, chevron-V and inverted-V) under 20 different ground motion records. The study reveals a satisfactory performance at the design intensity level for both types of braced frames. The results show that the SMA braces lead to a uniform distribution of inelastic response over the height of the buildings, as well as mitigating seismic response in terms of maximum inter-storey drift and residual roof displacement. By comparing the responses of SMA and buckling-restrained braced frames under higher intensities of earthquake loading, it is found that the SMA braces can be more beneficial especially under severe ground motion excitations.