Novel SMA Gear-Based BRB System for Seismic Retrofit: Development and Validation Using Hybrid Simulation

Abstract

In this research, a novel Shape Memory Alloy Gear-Based BRB System (SMA-GB-BRB) is developed for seismic retrofit of deficient structures. This system utilizes innovative design approach to achieve a symmetric, self-centering and non-sacrificial bracing system with a strain-amplification mechanism that allows for faster and more efficient energy dissipation during seismic events. This is achieved via the use of SMA, a smart material capable of reverting strain post yield, and a gear system that amplifies the sustained strain. Lab tests of the proposed system consisted of material testing, cyclic testing, and novel hybrid simulation testing. Testing of the proposed system proved it to be an effective method in the retrofitting of structures. The system successfully amplified strains by approximately two times, allowing for faster and more efficient energy dissipation. A bridge structure retrofitted with the proposed system experienced reductions in overall structural reaction, including reduced drift and reduced hinging of columns.