Fragility of Steel Frame Buildings under Blast Load

Abstract

Effects of different structural configurations, member orientations and standoff distances on blast-induced failure of steel frame buildings are investigated through development of fragility curves. Three steel frame buildings with different geometric configurations—square plan with rectangular shape in elevation, square plan with pyramidal shape in elevation, and semicircular plan with equal area at each floor level—are analyzed under blast load. The steel frame buildings are modeled, analyzed, and designed for dead load (DL), live load (LL) and seismic load (SL) for the National Capital Region (NCR), India. Force-controlled static nonlinear pushover analyses are performed to develop the fragility curves for the buildings under blast load. Different orientations of the columns (I-section) are considered to investigate the effect on building fragility under blast load. The results indicate significant effects of the structural configurations and column orientations on the blast resistance of the building. The pyramidal structure is found to be the most effective configuration in reducing the blast load effect on the structure among the considered configurations. It is also observed that the corner of a building is less critical in terms of blast load mitigation.