Coastal Bridge Reliability during Hurricane Events: Comparison of Fragility Curves by Static and Dynamic Simulation

Post-hurricane functionality of the transportation system is vital for emergency response and recovery activities. Coastal bridges are among the most critical components of the transportation system susceptible to hurricane induced wave and surge loads that may hamper this functionality. This study explores alternative approaches to develop probabilistic statements of coastal bridge damage potential conditioned upon hazard intensity, known as fragility. Fragility surfaces for a representative bridge structure of the Houston/Galveston area are developed using two different approaches: static analysis and nonlinear dynamic simulation. The static approach is efficient and can provide sufficient fragility models for simply supported bridges with limited connectivity between the super structure and substructure, since their predominant mode of failure is deck unseating or shifting due to connection failure. Nevertheless, for bridges with strong connection between sub and superstructure, the force transfer can cause other components to exceed their limit state. Hence the full dynamic behavior of structure becomes more critical in the fragility modeling of bridges with high strength connections.