Dynamic response and vulnerability analysis of pier under near-field underwater explosion

Marine reinforced concrete constructions (suspended tunnels, undersea pipelines, and cross-sea bridges) are inherently at risk from underwater explosions due to the rising incidence of worldwide terrorism. Sea-crossing bridges are as an important land-sea connection channel, whose anti-explosion performance cannot be ignored. In this paper, the dynamic response and damage mechanism of piers of sea-crossing bridge under underwater explosion loads are studied by the arbitrary Lagrangian-Eulerian (ALE) method. Firstly, the correctness of the explosive load and reinforced concrete material models is verified by the Zamyshlyaev formula and underwater explosion test, respectively. Secondly, the finite element (FE) model of a pier under an underwater explosion load is established. Taking the residual vertical bearing capacity of the pier as the performance index, the damage evaluation method and four damage levels of the pier under explosion load are put forward. The study of different parameters such as explosive weight, explosion location, explosion height, and explosion distance shows that the damage to the pier is the most serious when the detonation point is directly below the projection of the pier cap. The residual bearing capacity of the pier falls exponentially as explosive weight increases. Different detonation heights have significant effects on the damage to the pier. Additionally, it is found using the explosion vulnerability analysis approach that the pier is very susceptible to collapse when the explosive weight is 350 kg.