ارزیابی رانش باقیمانده احتمالی SMRFs با میراگرهای ویسکوز خطی و غیر خطی Probabilistic residual drift assessment of SMRFs with linear and nonlinear viscous dampers

1. Introduction Maximum Interstory Drift Ratio (MIDR) has been extensively used as an Engineering Demand Parameter (EDP) in most of the previous studies existing in the technical literature. MIDR is the maximum of all peak Interstory Drift Ratios (IDRs) observed along the height of a multi-story frame, where peak IDR for a particular story is the peak of the absolute values of IDR in the IDR time history response of the story. MIDR is a useful parameter to predict structural damage or collapse. Although collapse prediction is an important issue during life of structures, another question is that if structures can be used after strong ground motion or not. Recently, some researchers have focused on investigating Maximum Residual Interstory Drift Ratio (MRIDR) response of structures. Residual Interstory Drift Ratio (RIDR) for a particular story is the last (absolute) value of the IDR time history of the story. The MRIDR is the maximum RIDR of all the stories of the frame. Ruiz-García and Miranda [1] reported that the amplitude and height-wise distribution of residual drift demands strongly depend on building frame mechanism, hysteretic behavior of components, the height-wise system structural overstrength and ground motion intensity. Bojórquez and Ruiz-García [2] concluded that steel structures designed for MIDR demand subjected to narrow-band ground motion records may experience large permanent displacements that may lead to take the decision of demolishing them. Christopoulos et al. [3] reported that residual drift response strongly depends on post-yielding stiffness, maximum ductility demand and unloading stiffness of system. Ruiz-García and Aguilar [4] presented a procedure to evaluate the aftershock seismic performance of structures, which considers residual drift demands after the mainshock. The results of their study indicated that the collapse potential under aftershocks depends on the modeling approach. Moreover, it was concluded that the aftershock capacity corresponding to demolition (i.e., the aftershock capacity corresponding to reaching a residual interstory drift value that necessitates the demolition of structure) is lower than that of the aftershock collapse capacity, which means that this parameter is a better measure of the structure residual capacity against aftershocks. Sultana and Youssef [5] investigated the seismic performance of steel Moment Resisting Frames (MRFs) utilizing superelastic Shape Memory Alloys (SMAs). In their study, maximum and residual interstory drifts were used to assess the seismic performance of the structures considered. They showed that the optimum use of superelastic SMA in the beam to column connections could minimize the residual drifts of the structures. McCormick et al. [6] conducted a study to evaluate the psychological and physiological effects of residual drifts on occupants of buildings in Japan. They reported that residual interstory drifts of about 0.5% are perceptible for occupants of building, and reaching a residual interstory drift of 1.0% causes the dizziness of occupants. Thus, they suggested the residual interstory drift of 0.5% as the permissible residual drift level.