Blast loading effect of explosive weight distribution on RC columns

Explosive effects are commonly encountered on structures. The 2020 Beirut explosion, 9/11 attack in USA, or current Russia-Ukraine war cause significant structural destruction. Reinforced concrete (RC) members in compression are most vulnerable to blast loads. This paper deals with a numerical investigation on the propagation of damage and its effects due to distribution of explosives at different positions around a compression member for close range explosion. In this analysis, explosive weight and scaled distance are maintained constant throughout. The Arbitrary Lagrange Euler (ALE) algorithm along with Fluid- Structure Interaction (FSI) and Erosion algorithms, to accurately capture the blast effects have been employed. Models have been validated by assessing the damage profile and blast over- pressure. The concrete and reinforcement have been modeled using the Lagrange approach, while Eulerian method is adopted to model air and explosives. Coupling between the Lagrange and Eulerian part have been considered along with the contact between concrete and reinforcement. The strain contour reveals that damage propagation in a compression member varies with its cross-sectional size and the placement of explosives. Compression members with larger cross-sections exhibit a pronounced effect of explosive distribution, with damage penetrating to the core from the explosion side. In contrast, compression members with small cross-sections show reduced effectiveness of explosive distribution due to the small cross section size. In C900, plastic strain extends toward the core from the side of the explosion, whereas in C450, damage reaches the core from the opposite side of the explosion, leading to complete failure of compression member.