Multi-hazard Damage and Loss Assessment of Bridge Networks

The overarching objective of this study is to examine and compare the vulnerabilities of bridges combining effects of earthquake-induced ground shaking, ground failure (e.g., landslides and lateral spreading), and tsunami inundation. A parametric study is performed to understand the sensitivity of economic loss and traffic capacity with respect to the demand, resistance, and dispersion of the fragility functions of bridges for the combined hazards. The predicted damage varies substantially based on the selected fragility functions for the bridge structure. Additionally, when ground failure models are considered, there is an overwhelming increase in bridge damage and economic loss estimates, reinforcing the need for more refined ground failure analyses to reduce epistemic uncertainty. The loss estimates are significantly sensitive to fragility parameters, particularly the resistance models, emphasizing the need to develop more specific and systematic fragility functions suitable for an entire bridge inventory. Economic loss estimates based on these cascading hazards are ultimately provided with the M9.0 Cascadia Subduction Earthquake Zone scenario.