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Title |
Response Modification Factor of Precast Reinforced Concrete Moment Resisting Frame
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Authors |
무하마드 하룬(Muhmmad Haroon) ; 변현우(Hyun-Woo Byun) ; 이범식(Bum-Sik Lee) ; 김길희(Kil-Hee Kim) ; 이정윤(Jung-Yoon Lee) |
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DOI |
https://doi.org/10.4334/JKCI.2020.32.6.575 |
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Keywords |
프리캐스트 콘크리트; 모멘트 저항 골조; 반응수정계수 precast concrete; moment resisting frames; response modification/force reduction factor |
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Abstract |
Under severe seismic demands if structures are designed to remain within the elastic range, the results sections may highly be uneconomical because the maximum response acceleration is usually several times the maximum ground acceleration, depending on the structural stiffness and the magnitude of damping. Therefore, current design codes recommend much lower design seismic loads compared to the inertia loads for elastic response of structures by using the force reduction or response modification factor based on the equal energy dissipation concept. The response modification factor is used to reduce the actual base shear force to the design level force during an earthquake excitation. Various design codes i.e. ACI318-19, ASCE 7-10 etc. have come up with different R-factor values for different structural systems including the pre-cast moment frames. However, the Korean Concrete Institute design codes provide the R-factor values for cast-in place concrete moment frames along with other lateral load resisting systems but ignore the precast concrete structures. In this study, efforts are made to estimate the response modification factor for the precast RC moment resisting frames using nonlinear static push-over analysis. The types of the frames considered in this study are precast RC frames with strength and deformation capacity equal to 100 %, 75 % and 50 % of that of a monolithic RC frame. The result of this study shows that the R-factors of the three precast moment resisting frames were 6.5, 6.3 and 5.4, respectively.
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