Experimental and Numerical Study on the Residual Axial Capacity of RC Bridge Piers after Contact Explosion

摘要

Abstract Bridge piers damaged by accidental or deliberate explosions lose a portion of their axial carrying capacity, which can induce partial and/or complete collapse of the entire bridge structure. With the aim of evaluating blast-damage and establishing blast-resistant design approaches for bridge piers, the dynamic behaviors and residual axial-load-bearing capacities (ALC) of RC piers subjected to contact explosions were studied experimentally and numerically. First, five circular cross-sectional 1/2-scale RC piers, with a height of 3 m and diameter of 450 mm, were fabricated. A field contact-explosion test on three pier specimens was conducted using TNT charge weights of 0.5, 1.0, and 2.0 kg. Then, these three postblast plus another two intact RC piers were transported to the laboratory to experimentally examine the axial bearing capacities using a hydraulic testing machine. The test data obtained included the incident overpressure–time histories and quantitative postblast damage profiles of the piers, and full curves for the axial force-displacement. Second, corresponding high-fidelity finite-element (FE) models of both the contact explosion and the succeeding axial compression tests were established. The refined numerical simulations were performed by adopting the fluid–structure interaction, multimaterial arbitrary–Lagrangian–Eulerian, and erosion algorithms implemented in the FE program LS-DYNA. The material model and the FE analysis approach were comprehensively verified by comparing the numerical simulated results with the test data. A series of numerical simulations were also conducted on seismically designed prototype bridge piers in order to examine the parametric influences on the damage mode and residual ALC, and the corresponding damage index of the piers. Finally, based on the parametric study, several blast-resistant design suggestions are proposed for prototype RC bridge piers against contact explosions.