Blast Responses of Bridge Girders With Consideration of Isolation Effect Induced by Car Bomb

Abstract

Car bomb attack exhibits considerable different effects on structures when compared with the bare explosive blast. In this paper, a postdisaster investigation is presented for an existing bridge under accidental car bomb blast loading. Based on the analysis of the explosive properties, the crack distribution and deformation of the blast loaded girders are studied. Numerical analysis is conducted to verify the findings by simulating the truck isolation effect with steel plate. Both field data and numerical results indicate that the isolation effect of the vehicle can significantly affect the blast loading distribution on structures. Specifically, the shock wave propagation is isolated directly under the explosive source with the delayed arriving time. Peak values of overpressure within the steel plate isolating region are diminished while the pressures are magnified outside the isolating region due to reflection and wave merging. The results can be applicable to determine the essential blast-resistant design criteria to reduce the probability of blast induced failures.