Dynamic Analysis of RC Water Tanks under Explosion by Consideration Water-Structure Interaction

The issue of passive defense has become very important due to the increase of terrorist attacks around the world and the possibility of targeting various structures. One of these structures is water storage tanks which are very vulnerable to explosion and the destruction of this type of structure may be irreparable from in term of human, economic, and environmental parameters. The purpose of this study is to investigate the effect of the explosion on cyclic stresses and displacement created on the body of a cylindrical reinforced concrete tank with water storage due to hydrodynamic forces by considering the amount of water filling and the dimensions of the tanks. Also, according to the distances of 5 and 10 meters from the center of the explosion, the cyclic stresses created in the body of the tanks are investigated. For this purpose, Abacus commercial software has been used to numerically simulate three tanks with heights of 4, 6, and 8 meters and a fixed radius of 3 meters with a filling percentage of 0, 25, 50, 75, and 100 of water. The results show that with increasing the percentage of water filling, the hardness of the tank has increased and has caused the displacement of the body to have a decrease of 31.25% for a fully filled tank compared to an empty tank. Water filling also reduces the sensitivity of tanks to instability. The results show that the cyclic stresses of the tank body are affected by blast waves from the outside and water pressure from the inside so that the presence of water in the tank has caused the cyclic stresses in the body to increase by about 20 MPa.