The study of blast resistance of reinforced concrete columns has dramatically increased since the attack on the Alfred P. Murrah Building in Oklahoma City. Most of the research has concentrated on the response of columns to far-field blast loading. In certain cases the research has neglected the effects of reinforcement detailing or axial loading on the columns. This paper presents a numerical study to investigate the effects of axial loading on the response of reinforced concrete columns to blast loading from proximate explosions. A high-fidelity physics based finite element analysis tool, LS-DYNA, was used to model the reinforced concrete columns. The columns are subjected to free-air blast loading to evaluate the effects of axial loads on the response of concrete columns detailed in accordance with seismic detailing provisions of CSA A23.3-04. The results show that increased axial loading on reinforced concrete columns reduces the lateral deflection and the support rotation. Thus, columns in lower stories of high-rise buildings, where axial loading from gravity loads could be significant, are capable of resisting higher blast loading in comparison with similar columns in the low-rise buildings.
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