Impact-Fragility Analysis of Bridges under Vehicle Collision with Soil–Structure Interaction Effects

Abstract

Vehicle collision is an important reason for failing urban or highway bridges. However, few works have focused on the probability of damage to a bridge under such extreme loads. In this work, an impact-fragility analysis was conducted to calculate the probability of exceeding a damaged state of bridge systems, in which the probability of damage is conditional upon vehicle impact velocity, and soil–structure interaction (SSI) is included. Available impact tests of scaled vehicle–bridge pier systems conducted by previous researchers were utilized to validate the finite-element (FE) model and material models. Then, a three-span bridge with SSI was created for the fragility analysis using the validated high-fidelity FE method, in which the uncertainties of bridge materials and vehicle impact velocity were considered. The results indicated that SSI has a great influence on the dynamic performance of bridges; also, the probability of damage for each damage state increases significantly with the effects of SSI when the vehicle impact velocity is higher than a threshold value. The results also imply that boundary conditions of the bridge pier, the tonnage of the vehicle, and the pier diameter have a great effect on the threshold value of impact velocity leading to a damaged state.