Dynamic behavior of UHPC-FST under close-in explosions with large charge weight

Abstract

Ultra-high performance concrete filled steel tube (UHPC-FST) pier columns have great potential to apply in the bridge engineering due to the excellent structural and constructional performance, which are under the risk of car bomb attacks with close-in distance. Based on the field explosion test and numerical simulation, this study aims to examine the dynamic behavior of UHPC-FST specimens under close-in explosion with large charge weight. Firstly, the field explosion test was performed on five 1/4 scaled UHPC-FST specimens with TNT charge weight of 25 kg at scaled distances of 0.10–0.17 m/kg1/3, where the influences of standoff distance and burst height were assessed. It shows that the UHPC-FST possesses excellent blast-resistance since the specimens could maintain integrity under intensive blast loadings. Moreover, the different dynamic behaviors of UHPC-FST specimens obtained from present and previous explosion tests under large and small charge weights were also compared. Secondly, to further conduct the corresponding numerical simulation, the parameters of the Karagozian & Case Concrete (KCC) model were comprehensively calibrated for UHPC, and the finite element (FE) models of the field explosion test on UHPC-FST specimens were established by using the commercial software LS-DYNA. Finally, by comparing the damage mode and global deflection of UHPC-FST specimens between the test and simulation results, the calibrated KCC model parameters and the established FE model were fully verified. The present work could provide helpful references for designing and evaluating the blast-resistance of UHPC-FST.