This report describes the research and application of ground motion and damage correlation models affecting risk assessment for spatially distributed lifeline systems with specific emphasis on transportation networks. Deterministic and probabilistic seismic risks of the system are assessed for direct structural loss and network reliability. As a result of potentially underestimating system risk, high-cost economic decisions may be conservative.
Two different ground motion correlation models are developed and compared. The sensitivity of loss uncertainty to damage correlation is evaluated. These two different sources of correlation are observed to impact the loss coefficient of variation differently; however, this difference is not significant. It is demonstrated in this study that when ground motion and damage correlation are introduced, the loss distribution becomes increasingly heavy tailed for sample network applications. Furthermore, simulations for dependent link travel times resulted in three different optimal emergency routing configurations for the network application in this report.
Annual seismic risk exceedance curves for system loss and network reliability are developed, with and without correlations. These resulting bounds on risk are more informative to risk decision makers than a single point estimate of the loss.
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