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Title |
Investigation on the Effective Moment of Inertia of Reinforced Concrete Flexural Members Under Service Load
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Authors |
이승배 ; 박미영 ; 장수연 ; 김강수 ; 김상식 |
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Keywords |
유효 단면2차모멘트 ; 균열 단면2차모멘트 ; 휨 강성 ; 처짐 ; 사용하중 effective moment of inertia ; cracking moment of inertia ; flexural rigidity ; defection ; service load |
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Abstract |
The approaches in many design codes for the estimation of the deflection of flexural reinforced concrete (RC) members utilize the concept of the effective moment of inertia which considers the reduction of flexural rigidity of RC beams after cracking. However, the effective moment of inertia in design codes are primarily based on the ratio of maximum moment and cracking moment of beam subjected to loading without proper consideration on many other possible influencing factors such as span length, member end condition, sectional size, loading geometry, materials, sectional properties, amount of cracks and its distribution, and etc. In this study, therefore, an experimental investigation was conducted to provide fundamental test data on the effective moment of inertia of RC beams for the evaluation of flexural deflection, and to develop a modified method on the estimationof the effective moment of inertia based on test results. 14 specimens were fabricated with the primary test parameters of concrete strength, cover thickness, reinforcement ratio, and bar diameters, and the effective moments of inertia obtained from the test results were compared with those by design codes, existing equations, and the modified equation proposed in this study. The proposed method considered the effect of the length of cracking region, reinforcement ratio, and the effective concrete area per bar on the effective moment of inertia, which estimated the effective moment of inertia more close to the test results compared to other approaches.
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