Effects of Liquefaction on Structures in Christchurch

传统的液化评估程序无法解释2010-2011年坎特伯雷地震序列期间新西兰克赖斯特彻奇发生的不同程度的液化导致的建筑破坏。每一次事件对结构的影响都不同，值得进一步研究。基于性能的地震工程需要强大的分析工具，能够识别不同级别的地震性能。2010-2011年坎特伯雷地震序列以其出色的地面运动记录、全面的地下调查计划以及克赖斯特彻奇建筑物的良好记录性能，为改进液化评估工具提供了一个难得的机会。由于仅在实验室或通过数值模拟研究液化影响所固有的局限性，迫切需要使用这些记录良好的案例来获得洞察并开发改进的分析方法。克赖斯特彻奇的地面表征和地面破坏数据的数量和质量都是无与伦比的。因此，它们为推进液化工程方面的知识和实践提供了一个独特的机会。对克赖斯特彻奇麻烦的粉砂进行了取样和高级循环试验，以表征它们的循环阻力。这项工作能够全面记录在经历不同程度的液化引起的地面破坏的场地上的建筑性能的有洞察力的案例历史。实例的完全非线性有效应力反分析评价了土-结构相互作用效应对液化场地建筑物的重要性。此外，液化外展网站将把液化带入教室。从设计级地震中学习对于推动地震专业的发展是非常宝贵的。液化效应研究在美国至关重要，在美国，发生在克赖斯特彻奇的大规模液化可能会摧毁一座城市。克赖斯特彻奇的液化危害和基础设施与美国的相似，这意味着研究成果将直接转移到规模相当的美国城市，并可扩展到更大的城市中心。2010-2011年坎特伯雷地震序列提供了对建筑物区块进行综合研究的机会，其详细程度和复杂程度在美国由于安全限制而无法进行。重要的是，该研究关注的是液化对结构的影响，而不是液化现象本身，从而推动了液化工程的实践。该项目支持新西兰和美国地震研究人员之间持续的国际合作，并允许一名美国博士生在新西兰建立研究联系。

Conventional liquefaction evaluation procedures cannot explain the different levels of liquefaction-induced building damage that occurred in Christchurch, New Zealand during the 2010-2011 Canterbury earthquake sequence. Each event with its different effects on structures warrants further study. Performance based earthquake engineering requires robust analytical tools that can discern varying levels of seismic performance. The 2010-2011 Canterbury earthquake sequence, with its excellent recordings of ground motions, its comprehensive subsurface investigation program, and its well-documented performance of structures in Christchurch, provides an exceptional opportunity to advance liquefaction evaluation tools. With the limitations inherent in investigating liquefaction effects solely in the laboratory or through numerical simulations, there is a pressing need to use these well-documented case histories to gain insights and to develop improved analytical procedures. The quantity and quality of the ground characterization and ground failure data in Christchurch are unparalleled. Thus, they provide a unique opportunity for advancing knowledge and practice in liquefaction engineering. Sampling and advanced cyclic testing of the troublesome silty sands in Christchurch is performed to characterize their cyclic resistance. This work enables comprehensive documentation of insightful case histories of building performance at sites undergoing different levels of liquefaction-induced ground failure. Fully nonlinear effective stress back-analyses of the case histories evaluate the importance of soil-structure interaction effects for buildings at liquefaction sites. Additionally, a liquefaction outreach website will bring liquefaction into the classrooms. Learning from design level earthquakes is invaluable to advancing the earthquake profession. Liquefaction effects research is vitally important in the U.S. where the occurrence of the massive liquefaction that occurred in Christchurch could literally destroy a city. The similarity of the Christchurch liquefaction hazards and infrastructure with those in the U.S. means that the research findings will be directly transferable to U.S. cities of comparable size, as well as scalable to larger urban centers. The 2010-2011 Canterbury earthquake sequence provides the opportunity for an integrated study of blocks of buildings at a degree of detail and level of complexity that could not be performed in the U.S. due to security restrictions. Importantly, the research focuses on the effects of liquefaction on structures as opposed to the phenomenon itself, thus advancing the state-of-the-practice in liquefaction engineering. The project supports continued international collaborations between New Zealand and U.S. earthquake researchers and allows a U.S. Ph.D. student to establish research contacts in New Zealand.