Earthquake Disaster Resilience - From Mitigation to Recovery

近年来，世界经历了前所未有的地震损失。对于新西兰克赖斯特彻奇，一个与许多加拿大城市非常相似的社区，2011年2月6.3级地震的影响包括估计200亿美元的直接经济损失，大约70%的市中心建筑被拆除，包括50%以上的遗产建筑损失，CBD关闭超过18个月，以及数千名居民迁出。加拿大各市政当局已经认识到它们容易受到类似损失的影响，并努力制定计划，以提高它们的复原力。这项建议提供了一个全面的研究计划，以提高我们对建筑结构在地震中的性能的基本了解，最终目标是通过解决三个研究主题来提高加拿大社区的地震灾害抵御能力：(1)减轻现有脆弱建筑的风险，(2)提高新设计的性能，以及(3)改进震后评估方法。这项研究计划将有助于(1)通过寻求识别与坍塌潜力密切相关的旧混凝土建筑的特征。关于(2)的研究将侧重于两个分专题：首先，将过去地震造成的损失与结构系统实现更高性能所产生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，将对常用结构系统(例如混凝土核心墙建筑物)进行评估，以确定如何对其进行修改，以针对有限的设计方法变化实现更好的损伤容限。最后，对于(3)来说，抗灾能力的一个重要组成部分是在不过分保守的情况下有效地评估受损建筑的能力，以便它们能够尽快重新入驻。这一需要将通过建筑剩余能力与诸如裂缝宽度和非破坏性试验测量等可测量的损害指标相关联来解决。整个研究计划的一个值得注意的原创性方面是使用2011年克赖斯特彻奇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.