Earthquake Disaster Resilience - From Mitigation to Recovery

近年来，世界在地震中遭受了前所未有的损失。新西兰基督城与加拿大许多城市非常相似，2011年2月的6.3级地震造成的直接经济损失估计为200亿美元，市中心约70%的建筑被拆除，其中超过50%的遗产建筑被毁，CBD关闭超过18个月，成千上万的居民外迁。加拿大的市政当局已经认识到他们对类似损失的脆弱性，并努力制定方案来提高他们的恢复能力。本提案提供了一个全面的研究计划，以提高我们对地震期间建筑结构性能的基本理解，最终目标是通过解决三个研究主题来增强加拿大社区的地震抗灾能力：(1)减轻现有易危建筑的影响，(2)增强新设计的性能，(3)改进地震后评估方法。本研究计划将有助于(1)通过寻求识别与倒塌潜力密切相关的旧混凝土建筑的特征。对(2)的研究将集中在两个子主题上：首先，将过去地震造成的损失与结构系统实现更高性能的额外资本成本进行比较，以此为改变《建筑规范》的性能目标提供理由；其次，将对流行的结构系统（例如混凝土核心墙建筑）进行评估，以确定如何对其进行修改，以便在设计方法的有限变化下实现更好的损伤容忍度。最后，对于(3)来说，抗灾能力的一个重要组成部分是有效评估受损建筑的能力，而不是过度保守，这样它们就可以尽快重新使用。这一需求将通过建筑物剩余容量和可测量的损伤指标（如裂缝宽度和非破坏性测试测量）的相关性来解决。整个研究项目中一个值得注意的原始方面是使用2011年基督城地震的经验证据来验证模型，并确保研究结果与工程实践的相关性。

The world has experienced unprecedented losses from earthquakes in recent years. For Christchurch, New Zealand, a community very similar to many Canadian cities, the impacts of the February 2011 M6.3 earthquake include an estimated $20 billion in direct financial loss, demolition of ~70% of downtown buildings including loss of more than 50% of heritage structures, closure of the CBD for over 18 months, and outmigration of thousands of residents. Canadian municipalities have recognized their vulnerability to similar losses and strive to develop programs to improve their resiliency. This proposal provides a comprehensive research program to improve our basic understanding of the performance of building structures during earthquakes, with an end goal of enhancing earthquake disaster resilience of Canadian communities by address three research themes: (1) mitigation of existing vulnerable buildings, (2) performance enhancements for new designs, and (3) improved methods for post-earthquake evaluation. This research program will contribute to (1) by seeking to identify the characteristics of older concrete buildings closely correlated with collapse potential. Research on (2) will focus on two sub-topics: first, losses from past earthquakes will be compared with the additional capital costs of achieving higher performance from structural systems as a means of providing rationale for changes to the performance objectives of the Building Code; second, popular structural systems (e.g. concrete core wall buildings) will be evaluated to determine how they may be modified to achieve better damage tolerance for limited changes in design approaches. Finally, for (3), an essential component to disaster resilience is the ability to efficiently evaluate damaged buildings without undue conservatism such that they can be reoccupied as quickly as possible. This need will be addressed through the correlation of building residual capacity and measurable damage metrics such as crack widths and non-destructive test measurements. A notable original aspect integral to the entire research program is the use of empirical evidence from the 2011 Christchurch Earthquake to validate models and ensure relevance of research findings for engineering practice.