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چکیده
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The aim of this study is to consider seismic performance of steel moment-resisting frame (SMRF) structures, while adding different types of green roofs by endurance time (ET) method. These days, green roofs are welcomed by architects and engineers due to their beautiful architecture and many environmental benefits. In general, these roofs increase the weight of the structure at the highest elevation in different values 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. Determining the exact changes in the seismic behavior of structures due to the addition of green roofs to the existing structure is a challenging issue for engineers and usually requires a large amount of computational costs. In this research, different SMRF structures including 5, 10 and 15-story intermediate moment frames with ordinary roof, extensive and intensive green roof are modeled through a distributed plasticity (fiber) model. In this research, a statistical study based on the 630 nonlinear time-history analyzes for 7 earthquake records at different levels of excitation intensity and 27 nonlinear time history analyzes for 3 ET records were performed. The results show that adding extensive green roofs and intensive green roofs can increase the considered engineering demand parameter by about 15%, and 65%, respectively and the ability of the endurance time method to estimate the seismic performance of these structures is acceptable.
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