The Earthquake Engineering Online Archive

Stochastic characterization and decision bases under time-dependent aftershock risk in performance-based earthquake engineering

Yeo, Gee Liek; Cornell, C. Allin

PEER-2005/13, Pacific Earthquake Engineering Research Center, University of California, Berkeley, 2005-07, (400/P33/2005-13)

Aftershock probabilistic seismic hazard analysis (APSHA) is introduced. APSHA, similar to conventional mainshock PSHA, is a procedure to characterize the time-varying aftershock ground motion hazard at a site. A methodology is shown for quantifying, in probabilistic terms, the multi-damage-state capacity of buildings in different post-mainshock damage states. A time-dependent building\"tagging" policy (permitting or restricting occupancy) is then developed based on the quantification of life-safety threat in the aftershock environment using the probability of collapse as a proxy for fatality risk. Also developed are formal stochastic financial life-cycle cost models in both the post- and pre-mainshock environment. Both transition and disruption costs are included in the model. The traditional Poisson model is used for temporally homogeneous mainshocks and is extended to nonhomogeneous aftershocks. Further, the model is generalized to include renewal processes for modeling mainshock occurrences and Markov-chain descriptions of the damage states of a building. The analysis procedures are nonhomogeneous Markov and semi-Markov decision analysis and stochastic dynamic programming (Howard (1971)). A decision analytic framework under improving states of information is introduced for both the post- and pre-mainshock environment.

Available online: http://peer.berkeley.edu/publications/peer_reports/reports_2005/PEER513_YEO_cornell.pdf