Grant: Idea to Innovation

Research at UBC has resulted in the development of a self-centering bracing system known as the ""Piston Based Self-Centering Brace (PBSC)"" for seismic resistance of buildings. A bracing is a structural element installed diagonally in a structural bay of a building for resisting lateral loads. Traditional bracings built with structural steel sections essentially carry axial loads. Under axial tension, braces perform well. However, under compression, braces tend to buckle and lose their load carrying capacity. Researchers have proposed buckling restrained bracing, yielding bracing etc to overcome this buckling problem. However, they have other disadvantages including: a) heavy weight, b) fabrication difficulty, and c) potential to permanent damages after a large earthquake. Here, an innovative bracing system is proposed to overcome these shortcomings. The new bracing system will be light-weight, easy-to-fabricate, and will remain operational with no permanent damage even during a large earthquake. The proposed system intends to utilize superelastic shape memory alloy (SMA) bars installed inside a cylinder piston assembly, and has been patented in the US, Canada, and Japan. The bracing will be effective under both tension and compression. However, the SMA bars will be always under tension. Hence, the bracing will avoid buckling even under large compression and produce stable symmetric hysteresis loops. A properly designed braced frame structure could be operational even after a large seismic event due to its self-centering capability, increasing safety and survivability. It will also provide large savings in reduced repair work necessary in a post-disaster scenario, and potential for remediation in place rather than demolition. The significance of this research is paramount as this novel technology will help Canada improve the level of safety of infrastructure during earthquakes. This technology, combined with ancillary product engineering services for clients, is the basis for a new company, DuraBrace, which will lead the development and implementation of these products in key seismic markets in Canada and abroad, contributing towards more sustained economic growth in this sector and increased benefits to Canada.