Seismic Response Modification Factorof Reinforced Concrete Frames Basedon Pushover Analysis

Source:
By:Amira Elyamany Mohamed, Walid A Attia, Wael M. El-Degwy

DOI: https://doi.org/10.30564/jaeser.v2i2.818

Abstract:

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.

References:

[1] Egyptian Code for Calculation of Loads and Forces for Buildings, National research center for Housing and Building, Giza, Egypt, ECP-201, 2012. [2] Mwafy, A. M. and Elnashai A. S. Calibration of Force Reduction Factors of RC Buildings. Journal of Earthquake Engineering 2002, 6 (2): 239-273. [3] Newmark, N. M. and Hall W. J. Seismic Design Criteria for Nuclear Reactor Facilities. Report No. 46, Building Practice for Disaster Mitigation. National Bureau of Standards. U. S. Department of Commerce 1973, 209-236. [4] Blume. Allowable Stresses and Earthquake Performance. Proc. 6th World Conf. on Earthquake Engineering, Sarita Prakashan, Meerut, India 1977, 165-174. [5] Uang C. M. Establishing R (or RW) and Cd Factors for Building Seismic Provisions. Journal of Structure Engineering, ASCE 1991, 117(1): 19-28. [6] Assaf A. F. Evaluation of Structural overstrength in Steel Building Systems. Thesis Presented to Northeastern University, Boston, in Partial Fulfillment of The Requirements for The Degree of Master of Science, 1989. [7] Jain S. K., Navin N. Seismic Overstrength in Reinforced Concrete Frames. Journal of Structural Engineering. ASCE , 1995, 121(3): 580 – 585 [8] Miranda E. and Bertero V. V. The Mexico Earthquake of September 19, 1985-Performance of Low Rise Buildings in Mexico City. Earthquake Spectra, 1989, 5(1):121-143. [9] Kappos, A. J. Evaluation of Behaviour Factors on the Basis of Ductility and Overstrength Studies. Engineering Structures, 1999, 21(9): 823-835 [10] Eurocode 8, Design of Structures for Earthquake Resistance, Part 1: General Rules, Seismic Actions and Rules for Buildings, European Committee for Standardization, EC8, 2003. [11] Federal Emergency Management Agency, Prestandard and Commentary for the Seismic Rehabilitation of buildings, Washington, DC, U.S.A., FEMA-356, 2000. [12] Amar Louzai and Ahmed Abed, “Evaluation of the seismic behavior factor of reinforced concrete frame structures based on comparative analysis between non-linear static pushover and incremental dynamic analyses”. Bulletin of Earthquake Engineering, 2015, 13: 1773–1793. [13] Algerian seismic design code (RPA99/Version 2003). National Center of Applicated Research in Earthquake Engineering, Algeria, 2003. [14] Uniform Building Code, Volume 1, International Conference of Building Officials, California, U.S.A., UBC, 1997. [15] SAP2000, Integrated Software for Structural Analysis & Design, Version 15.1. CSI Computers & Structures, Inc., Berkeley, California, USA, 2010. [16] Egyptian Code for Design and Construction of Reinforced Concrete Buildings, national research center for Housing and Building, Giza, Egypt, ECP-203, 2007. [17] Amira, E. A. M. Evaluation of seismic response modification factor of reinforced concrete frames in the Egyptian code based on nonlinear static analysis. Thesis Presented to Faculty of Engineering, Cairo University, Egypt, in Partial Fulfillment of The Requirements for The Degree of Master of Science, 2016.