Shape memory alloy-based innovative self-centering civil infrastructure

民用基础设施占加拿大投资的很大一部分。地震等自然灾害对现有基础设施构成严重威胁。例如，在2011年新西兰克赖斯特彻奇地震中，估计约有200亿美元的经济损失（相当于新西兰GDP的13%）。地震造成了巨大的破坏，市中心约70%的建筑被毁。加拿大最近的一项研究显示了类似的情况，地震引起的潜在损失将分别给不列颠哥伦比亚省（远远超过其年度预算）和魁北克省（接近其年度预算）带来750亿美元和610亿美元的损失。***长期目标：为了应对这一问题，本提案提供了一个全面的研究计划，以开发新的结构元件和系统，这些结构元件和系统将具有增强的延展性和减少地震的永久变形。这可以通过使用超弹性形状记忆合金（SMA）作为增强材料来实现。SMA具有承受大的非弹性变形的能力，但在载荷解除后可以恢复其原始形状。在新的和有缺陷的结构中使用这种材料将减少基础设施故障的风险，并增强加拿大社区的地震抗灾能力。***近期目标：a)为新建工程开发自定心sma混凝土摇柱；b)发展近表面安装SMA钢筋的缺陷柱抗震加固技术；c)开发基于SMA钢丝的弹性支座抗震加固技术。尽管基于sma的结构在震区显示出巨大的潜力，但需要研究使这种结构体系更加有效和可靠。还需要制定设计准则，以便在民用基础设施中得到更广泛的应用。本研究项目将通过开发一种新型的SMA与钢筋连接的拼接机制，并在实验基础上制定SMA加固摇柱的抗震设计指南，为实现目标(a)做出贡献。对目标(b)的研究将侧重于制定使用近表面安装的SMA棒对缺陷桥墩进行抗震加固的指导方针。目标(c)的研究将实验研究基于sma的弹性体支座用于桥梁隔震的自定心性能。***从长远来看，这项研究将有助于加拿大满足智能结构的需求，并培养新型结构系统中的高素质人才（HQP）。这些高技能的HQP将通过在全球市场上引入新的结构体系，为加拿大经济做出重大贡献。这个研究项目的意义是至关重要的，因为它确保了对地震灾害的安全保障，并帮助加拿大避免了像2011年基督城地震这样的情况（市中心70%的建筑物被拆除）。

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.