Reinforced Concrete Element Resistance to Contact Explosion Effects and Mitigation

Protection of critical infrastructure and iconic buildings against terrorist attacks has become an integrated part of building design due to the ever-larger looming threats in today's environment. Consequentially, the response analysis of structures to blast loading has gained importance in the recent past. Blast loading is categorized as far-field, near-field and contact explosions in terms of the scaled distance to a building or structural element. Near-field and contact explosion events are characterized by a high-temperature fireball and extremely high magnitude, non-uniform overpressure. The existing empirical charts are inaccurate for scaled distances less than 0.4 m/kg1/3 and underpredict the blast parameters. Moreover, there are limited experimental tests on the response of reinforced concrete members subjected to contact explosion effects reported in the literature. Experimental tests on full-scale RC members subjected to live explosion is cost prohibitive and requires expertise for explosive handling. Thus, making live explosive testing outside the capability of many researchers. This thesis presents experimental and numerical studies on RC slabs, columns, and walls subjected to contact explosion effects and parametric studies to understand the response mechanism in order to recommend cost-effective mitigation strategies. An empirical equation to predict the breach diameter of RC slabs including the effects of reinforcement ratio and the contact area of explosive mass is presented in the thesis. The experimental tests on RC columns demonstrate that a significantly small amount of explosive mass can initiate failure in a column as compared to RC slab or wall with the same depth. Also, the damage phenomenon is predominantly local and global response is negligible in case of contact explosion events. Furthermore, it is shown that the gap offered by a column cladding can effectively mitigate contact explosion effects. Lastly, an increase in the width of an RC column transformed the failure mechanism from two-dimensional (2D) failure as in case of square RC columns to one-dimensional (1D) failure as in case of RC slabs. It was concluded that RC walls retained more than 25% residual axial capacity when subjected to breach threshold explosive mass for the same depth of RC slab.