• Magazine of the Korea Concrete Institute
• /
• v.6 no.2
• /
• pp.180-187
• /
• 1994

Sixteen reinforced concrete beams were tested statically up to failure to investigate the arch action. Major variables were the shear span to depth ratio, steel ratio and existence of stirrups.The arch action in reinforced concrete beams started when flexural cracks appeared at the center of the span. Due to the reduction of internal moment arm length by the development of arch action, the measured steel tension was significantly higher than the calculated. As the shear span to depth ratio arid steel ratio decrease, the arch action in reinforced concrete eams increases. Over the entire length the force in the steel of no web reinforced beams having smaller a /d ratio than 3 was constant because the beams acted as a tied arch.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.252-255
• /
• 2004

The measured longitudinal reinforcement tensions in the shear-critical RC beams were significantly higher than the calculated values by the beam theory. This may be attributed to the reduction of the internal-moment arm length by the development of the arch action. In this paper, the measured longitudinal reinforcement tensions in the test performed by $Kim^4$ were compared with those predicted by the various truss model.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.374-377
• /
• 2006

The measured longitudinal reinforcement tensions in the shear-critical RC beams were significantly higher than the calculated values by the beam theory. This may be attributed to the reduction of the internal-moment arm length by the development of the arch action. In this paper, the measured longitudinal reinforcement tensions in the test performed by Kim were compared with those predicted by the new truss model on the basis of the compatibility condition of the shear deformation.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1993.10a
• /
• pp.201-206
• /
• 1993

Four reinforced concrete beams without shear reinforcement were tested statically up to failure to investigate the arch action in reinforced concrete beams. Major variable was the shear span to depth ratio varied from 2 to 4. Due to the reduction of internal moment arm length by the development of arch action, the measured steel tension was higher than the calculated steel tension.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.181-184
• /
• 2008

In the case of RC beams simply supported, there is arch action that the length of internal lever arm varies through span. Recently the shear analysis model which considers this arch action has been developed, but this analysis model is only applicable to RC beams subjected to concentrated load. In this study, therefore, the fundamental relationship between internal lever arm length and applied moment is developed with considering general load such as uniformly distributed load. The shear compatibility condition is also derived, which is also applicable to RC beams subjected to uniformly distributed load. From the analysis results of RC beams, the variation of shear strains through span could be expected by the proposed analysis model. The magnitude of shear strains expected from analysis is so relatively small that the effect of shear force due to arch action should be considered on analysis.

• Magazine of the Korea Concrete Institute
• /
• v.10 no.6
• /
• pp.233-240
• /
• 1998

A rational expression, developed to predict the shear strength of reinforced concrete beams, is derived from the relationship between shear and the rate of change of bending moment along a beam coupled with experimental findings for the arch action. The proposed ultimate shear strength equation, arising from analytical premises and then calibrated with experimental data, is a similar form to the ACI 318 equation derived mainly from empirical approach. The proposed equation depends on the concrete compressive strength, amount of longitudinal steel content, and the shear span-to-depth ratio, and rationally reflects the shear resistance mechanism of combined beam action and arch action in reinforced concrete beams. The proposed equation applied to existing test data and the results were compared with those predicted by the ACI 318 equation and the Zsutty's equation.

• Journal of the Korea Concrete Institute
• /
• v.16 no.6 s.84
• /
• pp.785-794
• /
• 2004

This paper describes a new refined truss modeling technique derived based on the well-known relationship of V=dM/dx=zdT/dx+Tdz/dx in a reinforced concrete beam subjected to combined shear and moment loads. The core of the model is that a new perspective on the shear behavior can be gained by considering the variation of the internal arm length along the span, so that the shear resistance mechanism can be expressed by the sum of two base components; arch action and beam action. The sharing ratio of these two actions is determined by accounting for the compatibility of deformation associated to the two actions. Modified Compression Field Theory and the tension-stiffening effect formula in CEB/FIP MC-90 are employed in calculating the deformations. Then the base equation of V=dM/dx has been numerically duplicated to form a new refined truss model.