Local damage effects of reinforced concrete beams under contact explosions

In order to investigate the local failure modes and damage effects of reinforced concrete (RC) beams under contact explosion, the experimental studies of RC beams with the same size under different TNT charge masses were conducted. In the tests, the typical engineering scale RC prototype beams designed for frame structures were used as research objects. Through four independent explosion tests, the failure modes and damage characteristics of the RC beams were observed at different TNT charge masses, and the influence of different TNT charge masses on the local damage was analyzed. The results show that RC beams undergo four types of local failure modes such as front crater, side breakdown, back collapse and section punching under contact detonations. The depth of crater, thickness of the spallation, surface damaged area, and the deformation of the steel bars exhibited a linear increase with the cubic root of TNT charge masses. Based on the experimental data, the local damage degree could be divided into four grades: slight, moderate, serious and severe, that could be evaluated by the proportional charge criterion. The research results can provide a theoretical basis for designing the anti-blast structures and assessing the damage of components subjected to explosive loading.