• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.179-182
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• 2005

Recently, many design codes including ACI 318-02 recommend the use of a strut-tie model approach for design of structural concrete with D-region(s). However, there are several unclear problems and shortcomings in the codes' strut-tie model approach. A grid strut-tie model approach was proposed to resolve these problems. In this study, the ultimate strengths of 17 deep beams, the most familiar type of D-regions, were evaluated for the validity check of the grid strut-tie model approach. The analytical results obtained by the approach are compared with those by the strut-tie model approach presented by CEB-FIP, AASHTO LRFD, and ACI 318-02.

• Computers and Concrete
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• v.17 no.2
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• pp.157-172
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• 2016

This paper presents a Strut-and-Tie Model for reinforced concrete (RC) columns subject to lateral loading. The proposed model is based on the loading path for the post-yield state, and the geometries of struts and tie are determined by the stress field of post-yield state. The analysis procedure of the Strut-and-Tie Model is that 1) the shear force and displacement at the initial yield state are calculated and 2) the relationship between the additional shear force and the deformation is determined by modifying the geometry of the longitudinal strut until the ultimate limit state. To validate the developed model, the ultimate strength and associated deformation obtained by experimental results are compared with the values predicted by the model. Good agreements between the proposed model and the experimental data are observed.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.39-46
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• 1998

This paper is about design for diaphragm of prestressed concrete box bridge using strut-tie model. In this paper, equivalent loads for the diaphragm are computed by considering loading conditions on continuous prestressed concrete box bridge and analyses for both longitudinal section and transverse section of the diaphragm an done by considering the equivalent loading and the prestressing. Based on principal stress trajectory obtained from the analyses, strut-tie model for each sections are constructed. By analyzing the constructed strut-tie model for each sections, the amounts and the locations of reinforcement for the diaphragm are obtained. The application of strut-tie model in this paper shows that the design by soul-tie model for the diaphragm of prestressed concrete box bridges can be rationally performed.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.251-256
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• 1995

This paper presents an evaluation of the strength and behavior of a tested simply supported rectangular reinforced eoncrete beam and a design example of a shear wall using two-dimensional strut-tie model with finite element nonlinear analysis. Strut-tie models reflecting the actual support and loading conditions are developed for the beam and shear wall. The strut-tie model not only provides simple solutions for large number of design situations dealing with the entire range of concrete structures which appear to be rather complicated but also predicts the behavior and strength of concrete members.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.235-240
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• 2000

Although dapped-end beams are widely used in bridge and building structures, there are not any specific and reasonable design regulations on dapped-end beams. In this study, the validity of the suggested experimental and empirical design methods, conventional strut-tie model approach, and nonlinear strut-tie model approach is evaluated through the analysis of dapped-end beams tested to failure. The nonlinear strut-tie model approach proved to be the most suitable method for dapper-end beam design.

• Structural Engineering and Mechanics
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• v.44 no.2
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• pp.163-178
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• 2012

A strut-and-tie model is introduced in this paper to predict the ultimate shear strength of non-seismically detailed columns. The validity and applicability of the proposed strut-and-tie model are evaluated by comparison with available experimental data. The model was developed based on visible crack patterns observed on the test specimens. The concrete contribution is integrated into the strut-and-tie model through a concept of equivalent transverse reinforcement. To further validate the model a full-scale non-seismically detailed reinforced concrete column was tested to investigate its seismic behavior. The specimen was tested under the combination of a constant axial load, $0.30f_c{^{\prime}}A_g$ and quasi-static cyclic loadings simulating earthquake actions. Quasi-static cyclic loadings simulating earthquake actions were applied to the specimen until it could not sustain the applied axial load. The analytical results reveal that the strut-and-tie method is capable of modeling to a satisfactory accuracy the ultimate shear strength of non-seismically detailed columns subjected to reserved cyclic loadings.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.847-852
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• 2000

This paper presents an evaluation of the behavior and strength of two pre-tensioned concrete deep beams tested to failure with using the nonlinear strut-tie model approach. In the approach, the effective prestressing forces represented be equivalent external loads are gradually introduced along its transfer length in the nearest strut-tie model joints, the friction at the interface of main diagonal shear cracks is modeled by diagonal struts along the direction of the cracks in strut tie-model, and additional positioning of concrete ties a the place of steel ties is incorporated. Through the analysis of pre-tensioned concrete deep beams, the nonlinear strut-tie model approach proved to present effective solutions for prediction the essential aspects of the behavior and strength of pre-tensioned concrete deep beams.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.405-408
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• 2004

The current design procedures of ACI 318-02, CE3-FIP and NZS 3101 for interior beam-column joints do not provide engineers with a clear understanding of the physical behavior of beam-column joints. In this paper, the failure strengths of the interior beam-column joint specimens tested to failure were evaluated using the 3-dimensional strut-tie model approach, design criteria of ACI 318-02, ACI-ASCE committee 352 and Park and paulay, and softened strut-tie model approach. The analysis results obtained from the 3-dimensional strut-tie model approach were compared with those obtained from the other approaches, and the validity of the approach implementing a 3-dimensional strut-tie model was examined.

• International Journal of Concrete Structures and Materials
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• v.9 no.2
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• pp.255-266
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• 2015

A strut-and-tie based method intended for determining the load-carrying capacity of reinforced concrete (RC) corbels is presented in this paper. In addition to the normal strut-and-tie force equilibrium requirements, the proposed model is based on secant stiffness formulation, incorporating strain compatibility and constitutive laws of cracked RC. The proposed method evaluates the load-carrying capacity as limited by the failure modes associated with nodal crushing, yielding of the longitudinal principal reinforcement, as well as crushing or splitting of the diagonal strut. Load-carrying capacity predictions obtained from the proposed analysis method are in a better agreement with corbel test results of a comprehensive database, comprising 455 test results, compiled from the available literature, than other existing models for corbels. This method is illustrated to provide more accurate estimates of behaviour and capacity than the shear-friction based approach implemented by the ACI 318-11, the strut-and-tie provisions in different codes (American, Australian, Canadian, Eurocode and New Zealand).

• 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.