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Title |
Maximum Torsional Strength of Reinforced Concrete Beams (I) Maximum Torsional Reinforcement Ratio
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Authors |
이정윤(Jung-Yoon Lee) ; 김길희(Kil-Hee Kim) ; 신동익(DongIk Shin) |
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DOI |
https://doi.org/10.4334/JKCI.2021.33.5.519 |
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Keywords |
최대 비틀림강도; 입체트러스모델; 뒤틀림효과; 3차원 절점영역; 비틀림철근비 maximum torsional strength; space truss model; warping effect; three dimension nodal area; torsional reinforcement ratio |
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Abstract |
In concrete design codes, shear and torsion designs are related to each other. While the limitation of the maximum shear strength was revised in the KCI-21 code, the maximum torsional strength was not. As a result, the provisions of the KCI-21 code about the maximum shear strength are contradictory. The maximum torsional strength of the KCI-21 code is too conservative compared with that of the EC2-04 code and the CSA-14 code. In this paper, the maximum torsional strength was derived based on a space truss model. The torsional strength of the KCI-21 code considering the limitation of the maximum torsional reinforcement ratio overestimated the test results of 143 RC members. This is because, unlike a member subjected to shear, a bending compression region is not formed in a member subjected to torsion, and the concrete in a three-dimensional node region is easily spalled. In addition, additional compressive stress may be generated due to the warping effect. Therefore, it is necessary to reflect these influencing factors in the maximum torsional strength.
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