Hope for the Best, Prepare for the Worst: Response of Tall Steel Buildings to the ShakeOut Scenario Earthquake

Matthew Muto, & Swaminathan Krishnan

Published 2011, SCEC Contribution #1393

The USGS ShakeOut scenario was conceived as part of an effort to increase public awareness and readiness for the next big earthquake on the San Andreas fault through a large-scale emergency drill. To understand the effects of such an event, a source model for a M7.8 scenario earthquake was created and used in conjunction with a velocity model for southern California to generate simulated ground motions for the event throughout the region. This work represents an effort to develop one plausible realization of the effects of the scenario event on tall steel moment-frame buildings. We have used the simulated ground motions with three-dimensional non-linear finite element models of three buildings in the 20-story class to simulate structural responses at 784 analysis sites spaced at approximately 4 km throughout the San Fernando Valley, the San Gabriel Valley and the Los Angeles Basin. Based on the simulation results and available information on the number and distribution of steel buildings, the recommended damage scenario for the ShakeOut drill was 5% of the estimated 150 steel moment frame structures in the 10-30 story range collapsing, 10% red-tagged, 15% with damage serious enough to cause loss of life, and 20% with visible damage requiring building closure.

Citation
Muto, M., & Krishnan, S. (2011). Hope for the Best, Prepare for the Worst: Response of Tall Steel Buildings to the ShakeOut Scenario Earthquake. Earthquake Spectra: ShakeOut Special Issue, 27(2), 375-398.