Self-Centering Passive Base Isolation System Incorporating Shape Memory Alloy Wires for Reduction in Base Drift

Abstract

An earthquake is one of the most terrifying natural disasters that humans cannot control but use of proper technology can minimize its effect. Base isolation is one of the most widely implemented and well-known technique to reduce structural vibration and damages during an earthquake. This study proposes the use of SMA wires for the reduction in base drift while controlling the overall structure vibrations. The structure presented is a multi-degree of freedom (MDOF) structure along with base isolators and SMA wires in diagonal. Shape Memory Alloys (SMAs) are a new generation of smart materials with the capability of recovering their pre-defined shape after experiencing a large strain. The isolation bearing considered in this study consists of laminates of steel and silicon rubber. The performance of the proposed structure is evaluated and studied under different excitations including harmonic loading and seismic excitation. To assess the seismic performance of the proposed structure, shake table tests are conducted on base isolated MDOF frame structure incorporating SMA wires, which is subjected to incremental harmonic and historic seismic loadings. Root mean square acceleration, displacement and drift are analyzed and discussed in detail for each story. To better understand the structure response, percentage reduction of displacement is also determined for each story. The result shows that the reduction in the response of proposed structure is much better than conventional base isolated structure