Damage and Loss of Capacity of RC Columns Subjected to Close-In Detonations: An Experimental and Numerical Program

Abstract

The assessment of dynamic response and residual capacity of reinforced concrete (RC) columns to blast load is decisive for protection of buildings, especially regarding progressive collapse risk. In the case of explosive devices placed next to a critical structural element, complex and extreme loading is applied on the nearby system and the material response is characterized by high non-linearities. In this study, small-scale experimental tests have been performed at CEA-Gramat to investigate RC columns response for near-field detonations. By modifying the stand-off distance, different damage levels of RC column due to blast loadings have been obtained for a given charge weight. These results give information on the dynamic response of RC structure. The numerical simulation of reinforced concrete structures subjected to high velocity impacts and explosions remains a difficult task today. These difficulties are related to numerical aspects (convergence problems of the nonlinear stress strain relation in 3D problem, efficiency of the numerical procedure and robustness), but also to the ability of the material model to simulate the correct behavior of a very complex and heterogeneous material like concrete. Those works have led to the elaboration of PRM (Pontiroli, Rouquand & Mazars [1], [2], [3]) concrete model now routinely used to simulate the concrete response under a large range of dynamic loadings. The capabilities of the PRM model are illustrated by a restitution of RC columns response due to the blast effect. Numerical results are compared to experimental tests so as to evaluate simulation tools. In future works, residual load-carrying capacity of undamaged and blast damaged RC columns will be measured by axial compressive tests, and the loss of loading resistance will be analyzed.