Monday, April 22, 2013
Special Mechanical and Civil Engineering Seminar
Characterization of Ground Motions for Assessing Seismic Risk to Infrastructure
Jack Baker, Assistant Professor, Department of Civil and Environmental Engineering, Stanford University
Seismic risk assessment of buildings and infrastructure systems requires quantification of potential future ground motions, including their temporal and spatial variation across the relevant scales for a given problem. This talk will describe techniques to quantify spatial ground motion variation and temporal features of directivity from strong ground motion data. The application of these results for engineering analysis is then discussed. The proposed models are both seen to produce large impacts on estimated reliability of systems, such that decisions regarding design or retrofit of individual buildings or infrastructure systems are significantly affected by these results in some cases. As a case study, a model of the San Francisco Bay Area transportation network is considered, subjected to several thousand potential earthquake scenarios of varying magnitude and location. The functionality of the network after earthquake damage is considered, and it is shown that consideration of spatial correlation in ground shaking leads to an order-of-magnitude increase in the predicted probability of severe disruption to the network, relative to the case where this correlation is neglected. Implications for seismic risk management, and opportunities for further insights using geophysical simulations, are then discussed.