Evaluation of the Performance of Special Eccentrically Braced Frames against Seismic Progressive Collapse under Pulse-type Near-field Earthquakes

Document Type : Research Article


1 Department of Civil Engineering, Institute for Higher Education ACECR, Khouzestan, Iran

2 Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran


In the event of progressive seismic collapse, the entire columns are not removed and can weaken in a time-dependent manner. For example, the possibility of reducing the carrying capacity of a column is higher in the maximum acceleration of the ground. Therefore, since earthquakes have different parameters such as frequency content, maximum acceleration, effective vibration duration and other things, they can subject a structure to different effects. This is the special distinction of this phenomenon in contrast to progressive failure under gravity loads, which multiplies its importance. In this article, the ductility of simple and bending frames with special divergent bracing against progressive collapse is evaluated from a seismic point of view. The analysis used is non-linear time history analysis, according to 14 acceleration maps of the near-pulse area of FEMA P695 and non-linear static analysis, which was performed in SAP2000 software. The results showed that the maximum demand for the floor drift angle and rotation of the floor connecting beam in the two scenarios of removing the first and fourth floors for the special bending frame with special eccentrically bracing is 50% of the values of the simple frame with special eccentrically bracing. Except for the bending beam, in the scenario of removing the fourth floor, the maximum values of the floor drift angle for both frames were 0.024 radians and for the maximum rotation of the floor beam, 0.056 and 0.061 radians, respectively.


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