• Computers and Concrete
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• v.16 no.1
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• pp.163-178
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• 2015

Due to the increase of the use of precast concrete structures in multistory buildings, this paper deals with the behavior of an specific type of beam-column connection used in this structural system. The connection is composed by concrete corbels, dowels and continuity bars passing through the column. The study was developed based on the experimental and numerical results. In the experimental analysis a full scale specimen was tested and for numerical study, a 3D computational model was created using a finite element analyze (FEA) software, called DIANA. The comparison of the results showed a satisfactory correlation between loading versus displacement curves.

• Computers and Concrete
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• v.28 no.6
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• pp.621-634
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• 2021

For the reliable strut-and-tie model (STM) design of disturbed regions of concrete members, structural designers must accurately determine the strength of concrete struts to check the strength conditions of a selected STM el and the anchorage of reinforcing bars in nodal zones. In this study, the author proposed a consistent numerical method for strut strength, applicable to all two-dimensional STMs. The proposed method includes the effects of a biaxial stress state associated with tensile strains in reinforcing bars crossing a strut, deviation angle between strut orientation and compressive principal stress flow, and degree of confinement provided by reinforcement. The author examined the method's validity through the STM prediction of the ultimate strengths of 517 reinforced concrete (RC) deep beams, 24 RC panels, and 258 RC corbels, all tested to failure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5A
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• pp.443-462
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• 2010

The strut-tie model approach has proven to be effective in the ultimate analysis and design of structural concrete with disturbed regions. For the reliable analysis and design by the approach, however, the effective strength of concrete struts must be determined accurately. In this study, the validity of the effective strength of concrete struts, presented by the several design codes and many researchers including the author, was examined through the ultimate strength analysis of 24 reinforced concrete panels, 275 reinforced concrete deep beams, and 218 reinforced concrete corbels by using the conventional linear strut-tie model approach of current codes. The present study shows that the author's approach, resulting in an accurate and consistent evaluation of the ultimate strength of the panels, deep beams, and corbels, may reflect rationally the effects of primary variables including the types of strut-tie model and structural concrete, the conditions of load and geometry, and the strength of concrete in the strut-tie model analysis and design of structural concrete.

• Journal of the Korean Society for Advanced Composite Structures
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• v.4 no.2
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• pp.8-14
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• 2013

Deep beam shall be designed either by taking into account nonlinear distribution of strain or by Appendix A of Strut-and-Tie Models (STM) according to ACI 318(M) from version of 2002. Although STM is accepted as tool in design Discontinuity region (D-region) which mostly exist in Deep beam, Corbels, Dapped ends etc., it has been modified by many researchers. In this study we design deep beam by STMs which use simple truss for load distribution and the model of complex truss for load distribution compare with the ACI traditional which is designed by flexure design method and shear provided by concrete($V_c$) as provided in special provisions section of 11.8 in ACI 318-99 [1]. This study aims to find the different and efficiency of deep beam design based on variation of parameter compiled from many samples selected from ACI traditional and two model of STMs, simple and complex load distribution.

• Computers and Concrete
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• v.21 no.1
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• pp.95-102
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• 2018

Reinforced concrete corbel beams (span to depth ratio of a corbel is less than one) are designed with primary reinforcement bars to account for bending moment and with the secondary reinforcement placed parallel to the primary reinforcement (shear stirrups) to resist shear force. It is interesting to note that most of the available analytical procedures employ empirical formulas for the analysis of reinforced concrete corbels. In the present work, a generalized and a simple strut and tie models were employed for the analysis of reinforced corbel beams. The models were benchmarked against experimental results available in the literature. It was shown here that increase of shear stirrups increases the load carrying capacity of reinforced concrete corbel beams. The effect of horizontal load on the load carrying capacity of the corbel beams has also been examined in the present paper. It is observed from the strut and tie models that the resistance of the corbel beam subjected to combined horizontal and vertical load did not change with increase in shear stirrups if the failure of the corbel is limited by concrete crushing. In other words, the load carrying capacity was independent of the horizontal load when failure of the beam occurred due to concrete crushing.

• Journal of the Korea Concrete Institute
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• v.15 no.5
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• pp.689-696
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• 2003

Recently, Appendix A of ACI 318∼02 Code introduced the Strut-and-Tie Model(STM) procedure in shear design of deep flexural members. The STM procedure is widely used in the design of concrete regions where the distribution of longitudinal strains is significantly nonlinear, such as deep beams, beams with large openings, corbels, and dapped-end beams. Experimental study included five high-strength reinforced concrete deep beams with different detailing schemes for the horizontal and vertical reinforcement. The specimens were designed as simply supported beams subjected to concentrated loads on the top face and supported on the bottom face. At failure, all specimen exhibited primary diagonal crack running from the support region to the point load. Specimens which had mechanical anchorages(terminators) gives better representation of the load-carrying mechanism than the specimen had standard 90-degree anchorage at failure in deep flexural members. Based on the test results, shear design procedures contained in the ACI 318-99 Code, Appendix A of the ACI 318-02 Code, CSA A23.3-94 Code and CIRIA Guide-2 were evaluated. The Shear design of ACI 318-99 Code, Appendix A of the ACI 318-02 Code and CIRIA Guide-2 shown to be conservative predictions from 10% to 36% in the shear strength of the single-span deep beam which was tested. ACI 318-99 Code was the lowest standard deviation.