Blast-resistant design approach for RC bridge piers

Abstract

Piers are the critical components to support the superstructure of bridge, but susceptible to the intentional and accidental explosions due to its easy accessibility. The blast-induced damage to the pier may cause the entire bridge to collapse, resulting in huge casualties and economy loss, and thus it is necessary to perform the blast-resistant design for the bridge pier. At present, the analytical model and blast-resistant design approach for blast-loaded reinforced concrete (RC) pier considering both the direct shear and flexural responses were studied. Firstly, six shots of field ground explosion test on 1/5-scale circular and square RC columns were carried out, in which the TNT charges with the scaled distances of 0.86–1.22 m/kg1/3 were adopted. Then, the corresponding numerical simulations incorporating the newly developed Structured Arbitrary Lagrangian Eulerian (SALE) solver were conducted, and the validity of finite element (FE) analysis approach was verified by comparing the experimental incident and reflected overpressure-time histories acting on the periphery of pier with deviations for most measuring points less than 20%. Afterwards, total 176 explosion scenarios were numerically simulated, and a blast loading distribution model on the pier for ground explosions was proposed, which considers the pier cross-section shapes (circular and square) and pier diameter/edge length (0.2–1.6 m), the scaled distances of explosive charge (0.3–2.3 m/kg1/3), as well as the blast wave reflection and diffraction by the pier. Furthermore, a Timoshenko beam-based multi-degree of freedom (MDOF) analytical model was established, and validated by both the existing explosion tests on RC columns and refined numerical simulations of blast-loaded bridge piers with corresponding deviations no more than 5%. Finally, a blast-resistant design procedure incorporating the above-proposed blast loading distribution and MDOF models was given, providing a reliable and efficient blast-resistant evaluation and design tool for bridge piers.