Seismic Response Modification Factorof Reinforced Concrete Frames Basedon Pushover Analysis

Amira Elyamany Mohamed (BSc of civil engineering 2009, Faculty of engineering, Cairo University, Egypt MSc of structural engineering 2016, Faculty of engineering, Cairo University, Egypt E-mail address:
Walid A Attia (Professor of Structural Analysis and Mechanics, Structural Engineering Department, Faculty of Engineering, Cairo University, Egypt)
Wael M. El-Degwy (Professor of Reinforced concrete structures, Structural Engineering Department, Faculty of Engineering, Cairo University, Egypt)


Response modification factor is an essential factor in seismic analysis to provide economic design of reinforced concrete structures. Base shear force is divided by the response modification factor to consider the ability of the structure to dissipate energy through plastic hinges. The current study investigates the effects of changing some parameters on response modification factor (R-factor). Four groups of reinforced concrete frames were studied with different number of bays, number of stories, load pattern, and fundamental period of vibration. All reinforced concrete frames were analyzed using SAP 2000 then the straining actions results were used at specific excel sheets which are developed to design reinforced concrete members according to the Egyptian code of practice ECP-203 and ECP-201. Frames were analyzed by nonlinear static analysis (pushover analysis) using SAP2000. A sum of thirty two systems of frames was analyzed. According to the results, every frame has its unique value of R-factor. Accordingly, many parameters should be mentioned and considered at code to simulate the actual value of R-factor for each frame. Response modification factor is affected by many factors like stiffness, fundamental period of vibration, number of bays, frame height, geometry of the structure, etc. The given values of R-factor at ECP-201 can be considered conservative; as the accurate values of R-factor is higher than the given values.


Seismic analysis; Reinforced concrete frames; Egyptian code of practice ECP 201; Fundamental period of vibration; Nonlinear static analysis (pushover analysis); Load pattern

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