Economic and Safety Comparison of Different Performance Levels in the Design of Steel Buildings with Coaxial Bracing Frame against Explosion

Nowadays, with the increase of the terrorist attacks around the urban places, the building design under the blast loadings is of primary considerations, especially for some important buildings and vital arteries. When an explosion occurs, the blast waves can cause severe damage to the structure and endanger the lives of people. Since the existing steel structures are usually designed for the typical gravity and seismic loads, it is necessary to investigate their performances under blast loadings. In this study, analytical studies have been done for 2D structural models of simple steel frame system with concentrically bracing (CBF) with different number of stories 5 and 10 under blast loading. The nonlinear dynamic method is applied for analyzing and designed the studied models in SAP 2000 software according to UFC 3-340-02 instructions for blasting 1000 kg of TNT at a distance of 20 meters from the structure. Each of the structural models in this study is analyzed and designed by performance-based design method for three levels of high, low, and very low performance. Finally, the designs results from the performance method at different levels are compared in terms of economics and safety.