Probabilistic Seismic Demand Models and Fragility Estimates for Rc Bridges

A Bayesian methodology to construct probabilistic seismic demand models for the components of a structural system is developed. Existing deterministic models and obserational data are used. The demand models are combined with previously developed capacity models for reinforced concrete (RC) bridge columns to estimate the seismic fragilities of bridge components and systems. The approach properly accounts for all relevant uncertainties, including model error. Application to two bridge examples typical of modern California practice is presented.