Response Sensitivity for Probabilistic Damage Assessment of Coastal Bridges Under Surge and Wave Loading

The susceptibility of coastal bridges to damage during hurricane-induced storm surge has been illustrated along the U.S. Gulf Coast in several hurricane events. This factor poses a significant threat to the safety of nationwide transportation systems, effectiveness of postevent emergency response and recovery activities, and socioeconomic stability further afforded by functioning transportation infrastructure. Nationwide risk and loss assessment packages currently lack any reliable input models of bridge fragility to assess the risk to the transportation infrastructure posed by hurricane-induced storm surge and wave. However, these tools are essential for comparing the vulnerability of different bridge types, conducting regional risk assessment or loss estimates, and supporting decision making on risk mitigation activities. As a first step in the development of probabilistic models of bridge vulnerability subjected to hurricane scenarios, sensitivity studies are conducted to assess the significance of varying hazard and bridge parameters on the dynamic response of coastal bridges. Three-dimensional nonlinear finite element models are used to assess these demands under varying input modeling parameters, and an analysis of variance is conducted to evaluate the significance of each parameter. The sensitivity study reveals that the potential variation in wave parameters has the most statistically significant impact on the response of the bridge. Additionally, a second-level sensitivity study reveals that the most critical structural parameter is the deck mass followed by connection modeling parameters. The results of this study provide insight into modeling parameters that should receive careful treatment in probabilistic analysis of bridge vulnerability.