Shape memory alloy-based innovative self-centering civil infrastructure

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Civil infrastructure constitutes a significant portion of Canada's investment. Natural disasters, like earthquakes, pose a serious threat to existing infrastructure. For example, in the Christchurch (New Zealand) Earthquake in 2011, about $20 billion financial loss (equivalent to 13% of New Zealand's GDP) was estimated. The devastation was massive, including demolition of around 70% of downtown buildings. A recent study in Canada shows a similar picture where seismically induced potential losses will be $75 billion and $61 billion for the provinces of British Columbia (far exceeds its annual budget) and Quebec (nearly its annual budget), respectively. ***Long-Term Objective: To respond to this problem, this proposal provides a comprehensive research program to develop new structural elements and systems that will possess enhanced ductility and reduced permanent deformation against earthquakes. This can be achieved by utilizing superelastic shape memory alloy (SMA) as reinforcement. SMA has the ability to undergo large inelastic deformation but can regain its original shape upon load removal. Implementing such material in new and deficient structures will reduce the risk of infrastructure failure and enhance earthquake disaster resilience of Canadian communities.***Short Term Objectives: a) Develop self-centering SMA-based concrete rocking column for new construction; b) Develop seismic retrofitting technique for deficient columns with near surface mounted SMA bars; and c) Develop seismic retrofitting technique with SMA wire-based elastomeric bearing. Although SMA-based structures show significant potential for seismic regions, research is needed to make such structural systems more efficient and reliable. Design guidelines also need to be established for their wider use in civil infrastructure. This research program will contribute to Objective (a) by developing a novel splicing mechanism to connect SMA to steel rebar, and developing seismic design guidelines for SMA reinforced rocking column based on experiments. Research on Objective (b) will focus on developing guidelines for seismic retrofitting of deficient bridge piers using near surface mounted SMA bars. Research on Objective (c) will experimentally investigate the self-centering performance of SMA-based elastomer bearing for seismic isolation of bridges.***In the long-term, this research will help Canada meet the needs for smart structures and train high quality personnel (HQP) in novel structural systems. Such highly skilled HQP will be able to make significant contributions to Canadian economy by introducing new structural systems in the global market. The significance of this research program is paramount as it ensures improved safety and security against seismic hazards, and help Canada avoid a scenario like the Christchurch 2011 earthquake (demolition of ~70% of downtown buildings) during such an event.