• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.918-923
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• 2003

Reinforced concrete deep beams are commonly used in many structural applications, including transfer girders, pile caps, foundation walls, and offshore structures. The existing design methods were developed and calibrated using normal strength concrete test results, and their applicability th HSC deep beams must be assessed. For the shear strength prediction of high-strength concrete(HSC) deep beams, this paper proposed Softened Strut-and-Tie Model(SSTM) considered HSC and bending moment effect. The shear strength predictions of the refined model, the formulas the ACI 318-02 Appendix A STM, and Eq. of ACI 318-99 11.8 are compared with the collected experimental data of 74 HSC deep beams with compressive strength in the range of 49-78MPa . It is shown the shear strength of deep beam calculated by those equations are conservative on comparing test results. The comparison shows that the performance of the proposed SSTM is better than the ACI Code approach for all the parameters under comparison. The parameters reviewed include concrete strength, the shear span-depth ratio, and the ratio of horizontal and vertical reinforcement. The proposed SSTM gave a mean predicted to experimental ratio of 0.99, 32 percent higher than ACI 318-02 Code, however with the low coefficient variation.

• Magazine of the Korea Concrete Institute
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• v.16 no.1 s.78
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• pp.80-85
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• 2004

• 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.

• Structural Engineering and Mechanics
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• v.10 no.6
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• pp.589-601
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• 2000

A simplified analysis procedure utilizing the strut-tie modeling technique is developed to take a close look into the post-elastic deformation capacity of beam-column connections in ductile reinforced concrete frame structures. Particular emphasis is given to the effect of concrete strength decay and quantity and arrangement of joint shear steel. For this a fan-shaped crack pattern is postulated through the joints. A series of hypothetical rigid nodes are assumed through which struts, ties and boundaries are connected to each other. The equilibrium consideration enables all forces in struts, ties and boundaries to be related through the nodes. The boundary condition surrounding the joints is obtained by the mechanism analysis of the frame structures. In order to avoid a complexity from the indeterminacy of the truss model, it is assumed that all shear steel yielded. It is noted from the previous research that the capacity of struts is limited by the principal tensile strain of the joint panel for which the strain of the transverse diagonal is taken. The post-yield deformation of joint steel is taken to be the only source of the joint shear deformation beyond the elastic range. Both deformations are related by the energy consideration. The analysis is then performed by iteration for a given shear strain. The analysis results indicate that concentrating most of the joint steel near the center of the joint along with higher strength concrete may enhance the post-elastic joint performance.

• Steel and Composite Structures
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• v.44 no.5
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• pp.677-684
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• 2022

This paper reports experimental investigation on shear behavior of steel reinforced concrete (SRC) shallow floor beam, where the steel shape is embedded in concrete and the high strength bolts are used to transfer the shear force along the interface between the steel shape and concrete. Six specimens were conducted aiming to provide information on shear performance and explore the shear bearing capacity of SRC shallow floor beams. The effects of the height of concrete slab, the size and the type of the steel section on shear performance of beams were also analyzed in the test. Based on the strut-and-tie model, the shear strength of the SRC shallow floor beam was proposed. Experimental results showed that composite shallow floor beam exhibited satisfactory composite behavior and all of the specimen failed in shear failure. The shear bearing capacity increased with the increasing of height of concrete slab and the size of steel shape, and the bearing capacities of beam specimens with castellated steel shape was slightly lower than those of specimens with H-shaped steel section. Furthermore, the calculations for evaluating the shear bearing capacity of SRC shallow floor beam were verified to be reasonable.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.115-116
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• 2009

A new model which is able to understand the mechanical behavior is developed, based on investigating the theoretical background for design compressive strength in strut-and-tie model. A proposed model is an alternative method for engineers through analyzing the merits and demerits of the conventional models

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.577-582
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• 2000

This study is aimed to evaluate the shear strength of reinforced concrete deep beams subject to concentrated loads, using a simplified strut-tie model. For the shear strength prediction of deep beams, it is prerequisite to evaluate the effective width of strut and to verify the efficiency factors proposed by MacGregor et al.. The results analyzed by truss models have been compared with those calculated by domestic code for the existing data of 90 deep beam specimens. The shear strength of deep beams were reviewed with respect to concrete strength, the shear span-depth ratio, and the ratio of web reinforcements. The results showed that the shear strength of the proposed model gave a better agreement than the domestic code approach.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.6
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• pp.1-9
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• 2009

This study carried out a shear experiment on concrete deep beam reinforced AFRP to investigate the shear strength of deep beam. The test was conducted on 8 specimens, and the variables were shear span ratio, reinforcement ratio, effective depth, and rebar type. We compared shear strength using ACI 318-08 STM with proposed equations that considered arching action according to shear span ratio. As a result, it was found that shear strength of deep beam reinforced AFRP rebar presented higher shear strength than steel rebar. ACI STM's predictions are more accurate than other predicting equations, and thus this research proposed model versus effective compressive strength of the concrete strut that considered strut size effect based on test results. The predictions obtained using the proposed model are in better agreement than previous equations and codes.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.111-112
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• 2009

A thick footing is a D-region and it cannot be designed according to Bernoulli's beam theory. Using a smeared nodal zone and a fan, the thick footing is modeled based on an actual stress flow. A design procedure for determining a depth of the footing and an amount and a development length of reinforcement is provided.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.121-122
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• 2009

Currently, the design methods for coping of concrete piers predict over-reinforcements. In this study comparison and analysis of internal and external design codes is performed. Non-linear analysis using FEA and strut-tie model was done to reduce reinforcements embedded in coping of concrete piers.