Shear Strength of Members without Transverse Reinforcement Based on Development of Critical Shear Crack

2020 ◽  
Vol 117 (1) ◽  
Author(s):  
Francesco Cavagnis ◽  
João T. Simões ◽  
Miguel Fernández Ruiz ◽  
Aurelio Muttoni
Keyword(s):  
Shear Strength ◽  
Shear Crack ◽  
Transverse Reinforcement

Critical shear crack theory-based punching shear model for FRP-reinforced concrete slabs

2020 ◽  
pp. 136943322097814
Author(s):  
Xing-lang Fan ◽  
Sheng-jie Gu ◽  
Xi Wu ◽  
Jia-fei Jiang
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Shear Crack ◽  
Concrete Strength ◽  
Weight Ratio ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Crack Theory ◽  
Reinforced Concrete Slabs ◽  
Rc Slabs

Owing to their high strength-to-weight ratio, superior corrosion resistance, and convenience in manufacture, fiber-reinforced polymer (FRP) bars can be used as a good alternative to steel bars to solve the durability issue in reinforced concrete (RC) structures, especially for seawater sea-sand concrete. In this paper, a theoretical model for predicting the punching shear strength of FRP-RC slabs is developed. In this model, the punching shear strength is determined by the intersection of capacity and demanding curve of FRP-RC slabs. The capacity curve is employed based on critical shear crack theory, while the demand curve is derived with the help of a simplified tri-linear moment-curvature relationship. After the validity of the proposed model is verified with experimental data collected from the literature, the effects of concrete strength, loading area, FRP reinforcement ratio, and effective depth of concrete slabs are evaluated quantitatively.

scholarly journals Shear strength analysis of slabs without transverse reinforcement under concentrated loads according to ABNT NBR 6118:2014

2019 ◽  
Vol 12 (3) ◽  
pp. 658-693
Author(s):  
A. M. D. SOUSA ◽  
M. K. EL DEBS
Keyword(s):  
Shear Strength ◽  
Shear Force ◽  
Highway Bridges ◽  
Analytical Models ◽  
Strength Analysis ◽  
Transverse Reinforcement ◽  
Concentrated Loads ◽  
Technical Literature ◽  
Experimental Database ◽  
Small Areas

Abstract Concentrated loads in slabs without transverse reinforcement, usual in highway bridges, result in the horizontal spreading of the shear force towards the supports, situation in which not all the slab width contributes in the shear strength. Based on this, the analytical models of shear strength and punching capacity in slabs may not be suitable to deal with this loading. Since this topic is not widely discussed in the national technical literature, the paper aims to present contributions to these analyses with a focus on the accuracy level of the shear strength analytical models recommended by ABNT NBR 6118:2014. Therefore, the models available in the Brazilian code were applied to an experimental database with 118 test results and the results obtained by the Brazilian and European codes were compared. The results demonstrated that, as presented in the Brazilian code, shear strength model in one-way slabs can lead to unsafe resistance predictions while the punching capacity model can lead to very conservative predictions. From the analysis, it is concluded that considering the reduction of the shear force, in the case of loads distributed in small areas close to the support in slabs, and the use of more suitable procedures to define the effective width, it is possible to improve the level of accuracy of relations between experimental and theoretical values, but this still leads to high percentages of unsafe predictions of resistance (> 40%).

Design of Semilightweight Bridge Girders: Development-Length Considerations

2000 ◽  
Vol 1696 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Robert J. Peterman ◽  
Julio A. Ramirez ◽  
Jan Olek
Keyword(s):  
Shear Crack ◽  
Point Load ◽  
Critical Section ◽  
Tension Force ◽  
Transverse Reinforcement ◽  
Development Length ◽  
Bond Failure ◽  
Moment Capacity ◽  
Maximum Moment ◽  
Prestressed Reinforcement

In a recent study, 25 development-length tests were conducted on rectangular and T-shaped semilightweight beams having design compressive strengths of 48 MPa (7,000 psi) and 69 MPa (10,000 psi). In the rectangular beam tests, the design moment capacity was exceeded in every case. However, in the tests on T-shaped beams, bond failure occurred in some specimens immediately after the formation of a flexure-shear crack. Additional tests were then conducted on similar T-shaped beams having varying amounts of transverse reinforcement near the point load. These tests showed that bond failure could be prevented by increasing the transverse reinforcement near the point of maximum moment. The study showed that the shift in the tension force that occurs when flexural cracks turn diagonally may lead to bond failure if sufficient anchorage of the strand is not provided. Therefore, the investigators recommend that the current AASHTO requirements for strand development be enforced at a “critical section” located at a distance dp from the point of maximum moment toward the free end of the strand, where dp is the distance from the extreme compression fiber to the centroid of the prestressed reinforcement.

scholarly journals CONTRIBUTION OF CONCRETE TO SHEAR STRENGTH OF RC BEAMS FAILING IN SHEAR

2013 ◽  
Vol 19 (3) ◽  
pp. 400-408 ◽  
Author(s):  
Guray Arslan ◽  
Zekeriya Polat
Keyword(s):  
Shear Strength ◽  
Shear Failure ◽  
Plastic Hinge ◽  
Transverse Reinforcement ◽  
Rc Beams ◽  
Earthquake Resistant ◽  
Earthquake Resistant Structures ◽  
Shear Failures ◽  
Beam Plastic Hinge ◽  
Shear Demand

Reinforced concrete (RC) beams with light transverse reinforcement are vulnerable to shear failure during seismic response. In order to prevent brittle shear failures at beam plastic hinge regions of earthquake-resistant structures, the Turkish Earthquake Code and ACI318 require the use of sufficient transverse reinforcement to resist the total expected shear demand. These codes tend to be excessively conservative and, in some cases, the contribution of the concrete to the shear strength is neglected. The aim of this study is to investigate the contribution of concrete to shear strength of RC beams failing in shear experimentally. The beams were tested under monotonically increasing reversed cyclic loading to determine the concrete contribution to shear strength. It is observed that the concrete contribution to the shear strength at ultimate state ranges from 18% to 69% of the ultimate strength.

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