The Evaluation of the Special Moment Frame and Braced Frame Systems Performance under Blast Loadings in the Steel Structures

Nowadays، with the increase of terrorist attacks near the urban areas، the building design under the blast loadings is really significant، especially for some important buildings and vital arteries. When an explosion occurs، the blast waves can cause severe damages to the structures. Since the existing steel structures are usually designed to gravity and seismic loads، it is necessary to investigate their performances under blast loadings. In this study، analytical studies have been done for 3D structural models of special moment frames (SMF)، concentrically braced frames (CBF) and eccentrically braced frames (EBF) with different number of stories 3، 5 and 10. The Nonlinear dynamic method is applied for analyzing the models under two different levels of blast loadings. The blast load pattern and other criteria are based on the UFC 3-340-02. The plastic hinge rotation، ductility ratio، performance levels، brace axial forces، shear forces and flexural moments in all models are obtained from the analysis and compared with each others. The non-linear behavior is mostly observed in the front face columns due to the explosion location. It can be said that the structure performance is highly depended on the Peripheral elements under the blast loadings. Also، the EBF systems generally show the better performances than other systems under blast loadings.