Reza Ramezani Azghandi - M.Sc., Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran
Hamzeh Shakib - Professor, Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran
Maedeh Zakersalehi - Assistant Professor, Power Transmission & Distribution Research Center, Niroo Research Institute, Tehran, Iran

In this paper, seismic collapse response of steel high-rise buildings with dual lateral load resisting system is studied through finite element simulation. In order to obtain a reliable collapse simulation approach, first, special attention has been paid to numerical modeling details such as utilizing proper structural elements considering both accuracy and analysis-time efficiency, choosing and calibrating a proper fracture model, considering element removal capability and general contact algorithm. Then, step-by-step analysis of the collapse mechanisms is carried out for two ground motions with different frequency contents. Detailed collapse process of the considered structure demonstrates that for these two simulations, with wide and narrow frequency content of records, the behavior of the structure is notably different from the first stages of structural damages through collapse critical region formation and then final collapse mechanism. The results of this study demonstrate the importance of proper modeling technique for collapse simulation as well as the great effect of frequency content of record for identifying all possible collapse behaviors of structures

Collapse mechanism, High-rise building, Extreme Earthquake, Damage parameters, ABAQUS