RAPID: Investigation of Cascading Effects of the 2011 Japan Earthquake to Structural Damages of Bridges

该快速反应研究(RAPID)奖提供资金，用于开展一项探索性研究，重点是利用2011年3月11日日本东北太平洋沿岸地震的实际输入数据，对所选桥梁在长时间、高强度地震(包括主震和主震加余震)以及强震和海啸波浪力作用下的结构破坏进行建模。PIS将与他们的日本研究伙伴合作，后者正在收集地面运动和海啸波浪力记录以及其他有用的易腐烂信息；并将确定适合于初步调查结构破坏与长期地震荷载效应之间的相关性以及由连锁危险效应引起的桥梁的仪器和受损桥梁。根据现有资料，本次探索性研究中的现场数据收集重点将包括以下部分或全部：(1)按日本相对严格的抗震设计规范设计的结构，但由于主震持续时间长的特点，很可能在主震中受损；(2)桥梁在主震中幸存下来，损伤较小，但在后续余震中损伤较严重，甚至倒塌(包括地震和/或海啸引起的土壤液化效应)；(3)在主震地震、海啸水波力和漂浮残骸、汽车和船舶的冲击力共同作用下，位于危险区域的近海岸桥梁受损或坍塌；(4)由于桥梁上实施的结构保护系统的退化或丧失功能而导致的桥梁失效。这项探索性研究的结果将提交给美国国家科学基金会研讨会，以考虑未来与缓解土木工程基础设施系统的多重极端危险(包括连锁事件)相关的研究机会。这项研究还将有助于美日合作地震工程研究的继续进行，并将范围扩大到多个极端事件工程。此外，这项研究将提供一个机会，以培训博士后和研究生，以了解复杂的性质和挑战，以开发多种危险的弹性结构。

This Rapid Response Research (RAPID) award provides funding to carry out an exploratory study focused on modeling of structural damages of selected bridges subjected to long duration, high intensity earthquakes (including both mainshock alone and mainshock plus aftershocks), and strong earthquake followed by tsunami wave force by using actual input data of the March 11, 2011 Japan earthquake off the Pacific coast of Tohoku. The PIs will work with their Japanese research partners who are collecting ground motion and tsunami wave force records as well as other useful perishable information; and will identify instrumented and damaged bridges that are suitable for preliminary investigations on the correlations between structural damages and long duration earthquake load effects as well those due to cascading hazard effects. Based on information available, special emphasis for field data collection in this exploratory study will include some or all of: (1) the structures designed according to comparably strict seismic design codes of Japan, but damaged in the mainshock earthquake most likely due to the characteristic of long duration; (2) the bridges survived in mainshock earthquake with minor damages, but damaged more severely or even collapsed in sequential aftershock earthquakes (including earthquake and/or tsunami introduced soil liquefaction effects); (3) damaged or collapsed bridges near coast in hazard region due to combined actions of the mainshock earthquake, tsunami water wave forces associated with the impact forces from floating debris objects, cars and ships to impact the structures; (4) the bridge failure as a result of degradation or loss of function of structural protection systems implemented on the bridge.The results of this exploratory research will be presented to an NSF workshop for considering future research opportunities related to multiple extreme hazard (including cascading events) mitigation of civil infrastructure systems. The study will also contribute to continued US-Japan cooperative earthquake engineering research and expanding the scope to multiple extreme event engineering. Additionally, this study will provide an opportunity to train post-doctoral and graduate students to understand the complex nature and challenges to develop multi-hazard resilient structures.