عنوان مقاله [English]
From the viewpoint of building response to seismic ground motion, there are different seismic design methodologies. Currently, seismic design codes are based on the force method. However, the disadvantages of this method in neglecting important parameters, including structural vulnerability potential, as well as haracteristics of strong motion, have caused the improper performance of structures in past catastrophic earthquakes. Thus, seismic design methodology shifted to nonlinear methods, based on performance concepts, and, consequently, new methods, based on displacement, have been proposed in recent years for better evaluation of structural performance. Due to inherent weaknesses, such as dependency accuracy to ground motion characteristics,
incorporated in these design methods, it is expected that the energy method will advance and supersede current structural seismic design methods. Since the damage value of a structure caused by an earthquake is in a close relationship with the energy dissipation capacity of the structure, it can be anticipated that the energy based method will be a proper technique for evaluation of structural performance. In this study, the accuracy of the energy-based method in predicting the displacement demand of steel moment resisting frames of different storey numbers, under near-field and far-field earthquake records, is studied. To capture the accuracy of the energy-based method, the obtained results have been compared with the results of non-linear time-history
analysis. Taking into account the amount of energy transformed from the ground to structures, which has directed the correlation to spectrum velocity, its characteristics for near and far-field records are studied first. A new method, which depends on spectrum intensity (SI), is proposed for more accurate prediction of the energy transferred from earthquake records to structures. Finally, by examining the accuracy of this method, it is observed that the proposed method can significantly increase the result accuracy for any type of seismic excitation in predicting the displacement demand of frames.