Risk assessment of structures subjected to blast

Attacking city centers with pack portable bombs has become one of the regular terrorist attacks around the world. In these situations, life losses and injuries can be caused from various sources such as direct blast effects, structural collapse, debris impact, fire, and smoke. Casualties could increase when indirect effects are combined with closed exits or timely evacuation. So, calculating the annual risk of the structural collapses resulting from extreme loading conditions is subjected to many efforts. In this paper, the annual risk of blast-induced progressive structural collapse is calculated. The blast fragility is also calculated by a simulation procedure which generate possible blast configuration, and finally kinematic plastic limit analysis is used to verify the structural stability under gravity loading. As a case study, the blast fragility and the annual risk of collapse of a four-storey steel building are calculated.