Effect of concrete strength on the dynamic behavior of axially loaded reinforced concrete column subjected to close-range explosive loading

Abstract

In a structural system, the load-bearing columns are one of the most important and vulnerable structural members. The destruction of columns may lead to partial failure or even catastrophic progressive collapse of the structure, resulting in tremendous casualties and significant economic loss, as exemplified by the accidental detonation of 2,750 tons of Ammonium Nitrate in the Beirut City of Lebanon. Satisfactory structural response of columns with regards to maximum deflection under such extreme loading is one of the essential criteria for the survivability of the building and its users. In this paper, a finite element model of 300 mm × 300 mm experimentally tested square RC column of normal strength concrete (30 MPa) carrying axial compression subjected to an explosive load of 82 kg TNT is developed and validated using a high-fidelity program, ABAQUS/Explicit with concrete-damaged plasticity (CDP) model. Following validation, parametric study has been conducted by varying the concrete strength from 30 to 50 MPa following IS 4991: 1968 without altering the other design strength parameters. Dynamic responses including maximum displacement, damage dissipation energy, stresses, and crack patterns have been compared and discussed.