Analysis of steel-concrete composite column subject to blast

The single-degree-of-freedom method is commonly used to approximate the dynamic response of structures subjected to blast loading. One of the limitations of this method is that it cannot capture the multi-failure modes of the structural members. The rigid-plastic method is thus, proposed in this paper as an alternative analytical approach to estimate the blast response of concrete-filled steel composite columns. The rigid-plastic results are compared with single-degree-of-freedom calculations as well as numerical simulations in order to assess the competency of the proposed method. Due to the assumption of rigid-plastic material behaviour in the rigid-plastic analysis, the accuracy of this method is influenced by the extent of plastic deformation of the structural member. For the case of impulsive blast loading, the rigid-plastic estimations are found to be closer to the numerical results than those obtained using the single-degree-of-freedom method. Numerical analysis was also conducted to compare the performance of concrete-filled steel composite column to a reinforced concrete column. A significant improvement in the blast resistance of the composite column was observed from the comparison.