Analytical Study of Column Failure Due to Blast Loading

Abstract

The study of blast effects on structures has been an area of formal technical investigation for over 60 years. Over the past decade, the world has witnessed unprecedented levels of devastation from both natural disasters and terrorist attacks. 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 causalities. In addition, major catastrophes resulting from gas-chemical explosions result in large dynamic loads, greater than the original design loads, of many structures. Due to such impacts of large dynamic loading, efforts have been made during the past few decades to develop methods of structural analysis and design of blast resistance structure. Since blast resistant design is the important topic of study and therefore requires the careful understanding about the blast phenomena and its effect and impact on various structural elements. Columns in a building are vital structural elements which resist lateral loads during earthquakes therefor, they should be robust enough to resist blast loads since failure of even a few columns may initiate progressive collapse of a building. In the present report, a column from a steel-moment-framed building is subjected to blast loading scenarios for blasts occurring outside the building and at ground level. The explosive material, trinitrotoluene (TNT) is placed at various locations with variable charge weight and standoff distance. The selected column is modeled in ANSYSAutodyn ® maintaining its fixity and axial loads as in the main building. Response of the column is captured for different blast scenarios. Peak Reflected Pressure is calculated manually by Kinney and Graham approach and is compared with that obtained from Autodyn. A comparative study has been presented for different types of column sections subjected to blast loads due to different TNT weights and standoff distances. The findings are helpful in predicting the progressive failure of the building and also in deciding the orientation of columns in a building.