Test, design, and parametric analysis of a prefabricated industrial building with shape memory alloy (SMA) cable-restrained bearings for seismic resilience

Abstract

This paper presents an in-depth discussion on the behavior and design of a novel shape memory alloy (SMA) cable-restrained natural rubber (hereinafter denoted as SMA-NR) bearing used for multi-stage seismic protection of an industrial building equipped with critical facilities. The study commences with a brief illustration of the working mechanism of the bearing, followed by an individual SMA cable test and a full-scale quasi-static test on an SMA-NR bearing specimen. The SMA cable specimen exhibits a unique flag-shaped hysteretic behavior with large recoverable strain. The SMA-NR bearing test results present a double-stage hysteretic behavior, i.e., initial horizontally flexible performance and cable-restrained state for structural safety. Through a verified numerical modelling, and taking three structural responses into consideration, i.e., peak absolute acceleration, peak bearing deformation, and residual bearing deformation, an extended parametric study is conducted, covering different bearing types and restraining elements (SMA or steel cables). The system-level analysis results highlight the benefit of the SMA cable-restrained strategy in seismic isolation performance, and show a favorable efficiency of this strategy in trade-off of critical responses. Furthermore, a representative single-degree-of-freedom (SDOF) model is developed and well validated, with a satisfactory agreement to the overall structural model. Seismic fragility analyses are finally conducted considering both far-field and near-fault ground motions, indicating that the SMA cable restrainer, serving as the last-defense strategy, could effectively balance the various dynamic responses of the superstructure.