عنوان مقاله [English]
In this study, the capability of using the Endurance Time method in seismic analysis of steel moment frames with green roofs has been investigated. These days, green roofs are welcomed by architects and engineers due to their beautiful architecture and many environmental benefits. In general, this system significantly increases the weight of the structure at the roof level and leads to a change in the dynamic behavior of the structure. There are usually two categories of green roofs. The first category is extensive green roofs with short vegetation (such as grass) and usually low seismic weight. The second category is intensive green roofs with high vegetation (such as trees) and usually high seismic weight. Accurate evaluation of these types of structures has high computational costs. The Endurance Time method is a time history analysis that can seismically evaluate the structure at different levels of excitation intensity with low computational cost. Despite the advantages of this method, its performance in the seismic evaluation of different structures - especially when the seismic behavior of the structure is different from conventional structures - is a challenging issue. In this research, a 5 stories steel intermediate moment frame with ordinary roof, extensive and intensive green roof is modeled in Ansys software. Nonlinear finite element method is used for seismic assessment of these structures in various excitation levels. In this regard, both geometric and material nonlinearities are considered. To evaluate the accuracy of Endurance Time method, 7 earthquake records at different levels of excitation intensity have been used. The results show that the Endurance Time method with different accuracy can evaluate the maximum roof displacement, base shear and maximum interstory drift ratio compared to conventional time history methods. Also, adding a green roof can have a significant impact on the seismic behavior of this structure.