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Title |
Numerical Method for Effective Strength of Nodal Zones in Two-dimensional Strut-and-Tie Models
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DOI |
https://doi.org/10.4334/JKCI.2020.32.4.359 |
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Keywords |
콘크리트 구조부재; 스트럿-타이 모델; 절점영역; 유효강도; 깊은 보 structural concrete; strut-and-tie model; nodal zone; effective strength; deep beam |
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Abstract |
For an appropriate strut-and-tie model design of structural concrete, the effective strengths of nodal zones must be determined with sufficient accuracy. Many values and equations for effective strengths have been suggested. However, since the recommended strength values have been determined based on experimental works with specific geometry and loading conditions, it is inappropriate to use them in the strut-and-tie model design of general structural concretes. In this study, a new numerical method, that evaluates the effective strengths of two-dimensional nodal zones accurately and consistently by reflecting the state of stresses in the nodal zones, the effects of stresses and details of reinforcing bars placed inside and around nodal zones, and the compressive strength of concrete, is proposed. The ultimate strengths of 434 reinforced concrete deep beams tested to failure were estimated to verify the validity of the proposed method using the ACI 445 strut-and-tie model method with the existing and proposed effective strengths of nodal zones.
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