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

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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.