Vulnerability analysis of HSR bridge under near-field blast based on response surface method

Abstract

In this paper, the vulnerability analysis of a high-speed railway (HSR) bridge system attacked by the near-field blasts is conducted using the response surface method. An “explosive-air-ground” coupling analysis model is established by the ANSYS/LS-DYNA software. Through a comparison of the numerical simulated and the experimental results, the effectiveness of the Arbitrary Lagrangian Eulerian (ALE) algorithm and the accuracy of the analysis model are verified. Then, the dynamic responses of an HSR simply-supported bridge subjected to four types of car-bomb blasts are calculated. The damage levels of the bridge components are evaluated using the residual bearing capacities of the pier and beam, and the shear displacement of the bearings. By adopting the central composite design method, the response surface models for the evaluation indices of the bridge components are fitted. Furthermore, the failure probabilities of each component at various damage levels are calculated, and the vulnerability of the bridge system is analyzed based on the Boundary Estimation Method. The proposed method could predict the damage probability of the bridge system under various car-bomb blasts, and provide a reference for exploring a probability-based evaluation method for the post-blast safety of the HSR bridges.