Experimental and numerical study of damage characteristics of RC slabs subjected to air and underwater contact explosions

Reinforced concrete (RC) is one of the most commonly used construction materials. However, impact and blast loads could completely destroy RC structures, causing tremendous casualties and property losses. Therefore, analyzing the damage mechanism and dynamic behaviour of RC structures under blast loading is significant. This paper presents a study on the behaviour of RC slabs subjected to air and underwater contact detonation. Two RC slabs were tested under real blast loads. One was tested under air contact explosion of 210 g TNT, the other was tested subjected to underwater contact explosion of 6 g TNT. Damage evolution and damage mechanism of the RC slabs subjected to the air and underwater contact explosions are investigated by using high-fidelity numerical models. The damage patterns obtained from the numerical models match well with those of the tests. The effect of experimental environments on the structural behaviour of the slabs subjected to the underwater explosions is also discussed. The different response of the RC slabs subjected air and underwater explosions with identical charge mass are analyzed contrastively by employing the validated coupled method. The results show that the present model can give a reliable prediction of damage characteristics for RC structures under various blast scenarios. The experimental environments have important influence on the structural response and bubble development. The damage of the RC slabs induced by underwater contact explosion is significantly larger than that caused by air contact blast with equal charge mass.