Effect of Blast Loading on Steel Columns

In the past two decades, the explosive devices have become the weapon of choice for the majority of terrorist attacks. Several factors including accessibility of information bomb devices manufacturing, mobility and portability, coupled with significant property damage and injuries, are responsible for significant increase in bomb attacks all over the world. A bomb explosion within or immediately nearby a building can cause catastrophic damage on the building's external and internal structural elements including collapse walls, blowing out of large expanses of windows, and shutting down of critical life-safety systems. Loss of life and injuries to occupants can result from many causes, including direct blast-effects, structural collapse, debris impact, fire, and smoke. The indirect effects can combine to inhibit or prevent timely evacuation, thereby contributing to additional casualties. In some cases one or columns of the building are damaged which leads to failure of beam-slab systems above and thereby causing progressive collapse of the part of or entire structure. Thus, columns prone to blast are required to be investigated for high strain loading effects. In an attempt in this direction, this paper presents the modal analysis of a steel column taken from a large building frame subjected to blast loading. Implicit modal analysis was done to assess the robustness of numerical model prepared in explicit dynamic ANSYS.