Seismic analysis of non-structural components considering the interaction with the main structure and the effect of supporting soil

Abstract

Numerical simulations have shown that the interaction between a non-structural component (NSC) and the supporting primary structure can significantly affect the response of both the primary structure and the NSC. Previous studies have shown that the interaction, hereafter coined as the primary-secondary structure interaction (PSSI), depends on a number of factors, e.g. the dynamic properties of both the primary structure and the NSC, the attachment and location of the NSC, and the loading conditions. A primary structure founded on soil will respond to the behaviour of the soil and simultaneously, the soil responds to the dynamics of the structure, establishing an interaction often termed as soil-structure interaction (SSI). The response of the primary structure considering the effect of the supporting soil will consequently alter the response of the NSC. Experimental validations of the influence of the factors stated above had been scarce. Thus, the objective of this doctoral research is to investigate the influence of PSSI and supporting soil on the seismic response of NSCs through experiments. The first part of this doctoral research aimed to identify the factors that control the seismic performance of secondary structures. Small-scale models of single degree-of-freedom and multi degrees-of-freedom primary structures and a range of different NSCs with single supports were constructed and tested. Impact, harmonic and one-directional simulated earthquake loads were considered. An improved floor response spectrum approach including the influence of both PSSI and supporting soil was proposed based on empirical results. The later part of the research considered an NSC with multiple supports. Large-scale testing was implemented to study the transfer of load from the ground to each support of the NSC, which would otherwise be too small to detect in a small-scale setup. Multiplysupported NSCs can be particularly vulnerable to strong vertical excitations. Therefore, multi-axial excitations were considered in the experiments. To simulate a holistic system, the experimental models are designed to include both PSSI and soil effect. The outcome of the large-scale experiments highlights the crucial considerations for future seismic design of NSCs.