Seismic rehabilitation of existing concrete and masonry buildings

加拿大的几个大都市地区，包括维多利亚、温哥华和蒙特利尔，过去都经历过地震，将来肯定会经历地震。 这些地区的基础设施老化和人口密度增加，导致在发生大地震时建筑物、桥梁和公用设施遭受重大破坏的风险增加。 最近在加州和日本发生的地震表明，在20世纪70年代中期以前建造的混凝土和砖石建筑物特别容易受到重大的结构损坏，甚至倒塌。 但并非所有的混凝土和砖石建筑都对生命安全构成威胁，建筑业主对改造现有建筑的高成本感到沮丧，而工程师们则难以确定真正脆弱的建筑物可能在未来的地震中倒塌。需要进行研究，以帮助工程师和建筑业主面临通过地震修复降低城市中心现有结构地震风险的挑战性任务。 拟议的研究将努力消除混凝土和砖石建筑物抗震修复面临的障碍，从而最大限度地减少加拿大人面临的地震风险。 特别是，研究将集中在三个主题，旨在有助于提高对现有建筑物抗震性能的理解，从而使设计具有成本效益的改造策略：（1）强度退化对位移需求的影响;（2）无筋砌体墙的平面外响应对平面内剪切破坏的敏感性;材料劣化对既有建筑抗震性能的影响。

Several metropolitan regions in Canada, including Victoria, Vancouver, and Montreal, have experienced earthquakes in the past, and will most certainly experience earthquakes in the future. An aging infrastructure and an increase in population density in these regions has led to an increase in the risk of significant damage to buildings, bridges, and utilities in the event of a large earthquake. Recent earthquakes in California and Japan have demonstrated that concrete and masonry buildings constructed prior to the mid 1970's are particularly vulnerable to significant structural damage or even collapse. But not all concrete and masonry buildings pose a threat to life safety and building owners are frustrated with the high costs of retrofitting large inventories of existing buildings, while engineers struggle to identify the truly vulnerable buildings likely to collapse in future earthquakes. Research is needed to help engineers and building owners faced with the challenging task of reducing the seismic risk from existing structures in our urban centres through seismic rehabilitation. The proposed research will endeavour to remove obstacles facing the seismic rehabilitation of concrete and masonry buildings, thereby maximizing the reduction in seismic risk facing Canadians. In particular, the research will focus on three topics designed to contribute to an improved understanding of seismic performance of existing buildings, thereby enabling the design of cost-effective retrofit strategies: (1) the influence of strength degradation on displacement demands; (2) the sensitivity of out-of-plane response of unreinforced masonry walls to in-plane shear damage; and (3) the effect of material deterioration on the seismic performance of existing buildings.