M Pirayesh - M.Sc student, Iran University of Science and Technology, Tehran ۱۶۸۴۶, Iran
M A Shayanfar - Professor, Iran University of Science and Technology, Tehran ۱۶۸۴۶, Iran

In this investigation the Seismic behavior of Staggered Truss structures was evaluated. For this purpose, ۱۵ Models of Staggered truss structures, were varied by the number of stories (۴-, ۱۰-, ۲۰-stories) and the length of Vierendeel Panel, were designed in a high seismic risk zone. Then, based on the nonlinear static analysis, the seismic parameters of the structures, such as the over-strength factor, the Ductility factor, and the modification factor, R, were determined. According to this study if the vertical and diagonal chords remain linear under the seismic loads, the over-strength factor, the ductility factor and the modification factor of the structures greatly increase. Also by increasing the demand/capacity ratios and decreasing the length of Vierendeel panels, the ductility of the structures increases. Nonlinear analysis was also shown that the seismic parameters of structures decrease and the weight of structural materials per unit area increase while the number of stories increase

staggered truss; pushover analysis; steel frame design; ductility; modification factor