طراحی لرزه ای سازه ها با استفاده از "روش ضریب رفتار اصلاح شده"

The traditional procedure for seismic design of building structures has been generally termed the force-based design (FBD) method. In the FBD method, the elastic seismic force acting on the structure is calculated first with the aid of a design acceleration response spectrum. This elastic force is then divided by a reduction factor called behavior factor R, representing the ductility and overstrength capacities of the structures. The implementation of FBD in seismic codes, does not clearly define the performance level. Furthermore, this method assumes the constant behavior factor values for the structures with the similar types of the lateral load resisting systems and do not take into account structure numeral properties same as the influence of the number of stories. These are some disadvantages of the FBD method that have been referred in many researches. So recently, procedures have been developed to substitute for this method. The design procedure would be more rational if the performance of the structure was quantified through a target value of deformation treated as an input variable in the design procedure. This target value of deformation can be assigned to different performance objectives and is the starting point for the development of the rather new displacement-based seismic design (DBD) method and is described in the some guidelines and publications as a performance-based seismic design method. The third and newest seismic design method is called the hybrid force/displacement-based design (HBD) method that adopts the seismic design philosophy based on both the resistance performance-based seismic design method. The third and newest seismic design method is called the hybrid force/displacement-based design (HBD) method that adopts the seismic design philosophy based on both the resistance and the performance. The HFD method combines the best elements of the FBD and DBD methods and tries to avoid those ones, which are usually thought of as disadvantages. This research proposes a new hybrid force/displacement-based seismic design method that is named the modified behavior factor (MBF) method. The MBF method combines the FBD method of the Iranian Earthquake Resistance Design Code (Standard No. 2800) and the DBD method of the Iranian Instruction for Seismic Rehabilitation of Existing Buildings (Publication No. 360). Two 5 and 7 story frames with three bays have been seismically designed by the MBF and the FBD methods and the results of them have been compared. The seismic responses of the MBF method are more precise than the responses of the FBD method.