Behaviour of concrete deep beams with openings and low shear span-to-depth ratio

Seven steel-reinforced concrete (SRC) deep beams were tested to investigate the shear performance, including peak loads, failure modes, mid-span deflections, and cracking patterns. The parameters include the shear span-to-depth ratio and the dimensions of the steel skeleton. The digital image correlation (DIC) technique was utilized for real-time recording of the in-plane strain and deformation. The experiment results show that the failure modes of specimens could be concluded as two forms: diagonal compression failure and shear failure. The DIC technique was proved to be efficient for tracking the development of crack patterns and recording the failure modes. The corresponding numerical analyses based on experiments were carried out and demonstrated to be a reliable method to simulate the shear response. Furthermore, the most significant parameters and their interactions were identified by finite element models parameter analysis. The steel skeleton height and shear span-to-depth ratio were the main parameters affecting shear capacity. A design formula based on the strength superposition method was presented. The calculated results were basically in agreement with the test results, where the mean and coefficient of variation were 1.04 and 0.09, respectively.

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Experimental Study on Shear Capacity of High Strength Reinforcement Concrete Deep Beams with Small Shear Span–Depth Ratio

Materials ◽

10.3390/ma13051218 ◽

2020 ◽

Vol 13 (5) ◽

pp. 1218 ◽

Cited By ~ 3

Author(s):

Jun-Hong Zhang ◽

Shu-Shan Li ◽

Wei Xie ◽

Yang-Dong Guo

Keyword(s):

High Strength ◽

Shear Capacity ◽

Reinforcement Ratio ◽

Longitudinal Reinforcement ◽

Deep Beams ◽

Shear Span ◽

Depth Ratio ◽

Diagonal Compression ◽

Web Reinforcement ◽

Small Shear

This study aimed to investigate the shear capacity performance for eight deep beams with HTRB600 reinforced high strength concrete under concentrated load to enable a better understanding of the effects of shear span–depth ratio, longitudinal reinforcement ratio, vertical stirrup ratio and in order to improve design procedures. The dimension of eight test specimens is 1600 mm × 200 mm × 600 mm. The effective span to height ratio l0/h is 2.0, the shear span–depth ratio λ is 0.3, 0.6 and 0.9, respectively. In addition, the longitudinal reinforcement ratio ρs is set to 0.67%, 1.05%, 1.27%, and the vertical stirrup ratio is taken to be 0%, 0.25%, 0.33%, 0.5%. Through measuring the strain of steel bar, the strain of concrete and the deflection of mid-span, the characteristics of the full process of shear capacity, the failure mode and the load deflection deformation curve were examined. The test results showed that the failure mode of deep beams with small shear span–depth ratio is diagonal compression failure, which is influenced by the layout and quantity of web reinforcement. The diagonal compression failure could be classified into two forms: crushing-strut and diagonal splitting. With decreasing of shear span–depth ratio and increasing longitudinal reinforcement ratio, the shear capacity of deep beams increases obviously, while the influence of vertical web reinforcement ratio on shear capacity is negligible. Finally, the shear capacity of eight deep beams based on GB 50010-2010 is calculated and compared with the calculation results of ACI 318-14, EN 1992-1-1:2004 and CSA A23.3-04, which are based on strut-and-tie model. The obtained results in this paper show a very good agreement with GB50010-2010 and ACI 318-14, while the results of EN 1992-1-1:2004 and CSA A23.3-04 are approved to be conservative.

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Effect of Shear Span to Effective Depth Ratio on the Behavior of Self-Compacting Reinforced Concrete Deep Beams Containing Openings Strengthened with CFRP

Association of Arab Universities Journal of Engineering Sciences ◽

10.33261/jaaru.2019.26.1.001 ◽

2019 ◽

Vol 26 (1) ◽

pp. 1-9

Author(s):

Nabeel A. Al-Bayati ◽

Bassman R. Muhammed ◽

Muroj F. Oda

Keyword(s):

Reinforced Concrete ◽

Ultimate Load ◽

General Trend ◽

Load Path ◽

Deep Beams ◽

Web Openings ◽

Shear Span ◽

Depth Ratio ◽

Effective Depth ◽

Strengthened Beam

Results of test on seven simply supported self-compacting reinforced concrete deep beams, including six of these beams containing circular openings in center of load path are reported in this paper. The objective of the tests was determined the influence of, changing shear span to effective depth ratio a/d, the existence of circular openings in shear span and using inclined strips of carbon fiber polymer (CFRP) on behavior of deep beams. The general trend in crack pattern, the load-deflection response, and the mode of failure of reinforced SCC deep beams were also investigated. All specimens had the same geometry, details of the flexure and shear reinforcement in both vertical and horizontal directions and they were tested under symmetrical two-point loads up to failure. The experimental results revealed that the web openings within shear spans caused an important reduction in the deep beam capacity by 50% when compared with the corresponding solid beam. The increase a/d ratio from 0.8 to 1.2 decreases the ultimate load by 21.7% and 22.5 % for the reference unstrengthened beam and strengthened beam, respectively, also it was found that the externally inclined CFRP strips in deep beams increased the ultimate strength up to 39.5%, and enhanced the stiffness of deep beams with openings.

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Numerical Verification of Strut and Tie Models and Failure Modes of Reinforced Self-Compacting Concrete Deep Beams

International Journal of Engineering Research in Africa ◽

10.4028/www.scientific.net/jera.53.76 ◽

2021 ◽

Vol 53 ◽

pp. 76-100

Author(s):

Mutiu Adelodun Akinpelu ◽

Bilyamin Adeoye Ibitoye ◽

Samson Olalekan Odeyemi ◽

Kabir Opeyemi Olorede

Keyword(s):

Failure Modes ◽

Concrete Strength ◽

Numerical Verification ◽

Nonlinear Behaviour ◽

Finite Model ◽

Deep Beams ◽

Self Compacting Concrete ◽

Shear Span ◽

Strut And Tie ◽

Depth Ratio

This study utilized Finite Element Method (FEM) to analyse the structural behaviour and failure modes of Reinforced Self Compacting Concrete (RSCC) deep beams. Eighteen deep beam specimens subjected to four-point loadings were modelled and analyzed using Abaqus modelling tool. Damage plasticity model was used to characterised the nonlinear behaviour of concrete material while linear elastic, linear-plastic-hardening model represented the reinforcing steel material behaviour. The results of the finite model were compared with four different Strut and Tie Models (STMs) using one-way Analysis of Variance (ANOVA). Results of the numerical study revealed that the concrete strength and shear span to depth ratio mostly affect the load-deflection response of the beams. Also, the failure modes of the studied deep beams were influenced by shear span to depth ratio, concrete strength as well as web reinforcement distribution. The ANOVA results also showed that the FEM outperformed the existing STMs.

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Behavior of High-Strength Self-Consolidated Reinforced Concrete T-Deep Beams

The Open Construction and Building Technology Journal ◽

10.2174/1874836802014010051 ◽

2020 ◽

Vol 14 (1) ◽

pp. 51-69

Author(s):

Hayder H. H. Kamonna ◽

Qasim M. Shakir ◽

Haider A. Al-Tameemi

Keyword(s):

Reinforced Concrete ◽

Failure Load ◽

High Strength ◽

Deep Beam ◽

Deep Beams ◽

Strength Concrete ◽

Shear Span ◽

Depth Ratio ◽

Load Beam ◽

Failure Loads

Background: When a beam is loaded on two opposite faces and the beam’s depth is increased such that either the span-to-depth ratio is smaller than four or the shear-span-to-depth ratio is less than two, it will behave like a deep beam. Strain distribution in deep beams is different from that of ordinary beams because it is nonlinear along with the beam depth. If the beam is cast monolithically with a slab in the slab–beam system, it is considered a T-deep beam. The behavior of the resulting member is more complicated. Objective: The effect of flange width on the behavior of high-strength self-consolidated reinforced concrete T-deep beams was investigated. Methods: Experimental and numerical studies were conducted. Two shear span-to-depth ratios (1.25 and 0.85) were adopted for two groups. Each group consisted of four specimens: one rectangular beam that served as a reference beam and three flanged beams with flange widths of 440, 660 and 880 mm. All specimens had an overall depth of 450 mm, a width of 160 mm and a total length of 1600 mm. The tests were performed under a two-point load with a clear span of 1400 mm. A nonlinear analysis was also performed using ANSYS software. Results: Throughout the study, the performance of the T-deep beams has been investigated in terms of cracking loads, failure loads, modes of failure, loading history, rate of widening of cracks and ductility index. Results revealed that such parameters have a different ranges of effect on the response of T-deep beams. Calibration of the ANSYS model has been done by comparing results of load-deflection curves, cracking and failure loads with that obtained experimentally. Conclusion: The study’s results indicated that increasing the flange width yielded an 88% improvement in the failure load and an approximately 68% improvement in the cracking load. This positive effect of flange width on the failure load was more pronounced in beams with higher shear span to- depth ratios and flange widths of 660 mm. In addition, the beam’s ductility was improved, especially in cases corresponding to a higher shear span-to-depth ratio. The finite element simulation showed good validation in terms of the load-deflection curve with a maximum failure load difference of 9%. In addition, the influence of longitudinal steel reinforcement on the behavior of such members was studied. Some parameters that reflect the effect of changing the flange width on the behavior of deep beams were also presented. Increasing the flange width is more effective when using normal strength concrete than when using high-strength concrete in terms of cracking load, beam stiffness, and failure load.

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Effect of shear span-to-depth ratio on posttensioned concrete crane beams shear capacity

MATEC Web of Conferences ◽

10.1051/matecconf/202032301019 ◽

2020 ◽

Vol 323 ◽

pp. 01019

Author(s):

Wit Derkowski ◽

Rafał Walczak

Keyword(s):

Shear Capacity ◽

Industrial Plant ◽

Shear Span ◽

Depth Ratio ◽

Standard Design ◽

Posttensioned Concrete ◽

Arch Action ◽

The Subject ◽

Brittle Mode ◽

Low Shear

The shear span-to-depth ratio has the most significant influence on the shear capacity of beams and determines their failure mode. The subject of the current project is the shear capacity of precast posttensioned concrete crane beams disassembled after more than fifty years of being used in an industrial plant. The paper gives the theoretical basis for the shear capacity of such elements as well as standard design models. The conducted tests showed that despite the low shear reinforcement ratio, the elements do not fail in a brittle mode but show a clear indication of prospective destruction. It was also confirmed that in the case of poorly shear-reinforced PC elements, a clear arch action can be distinguished with a low shear span-to-depth ratio, whereas in the case of a higher ratio there is a classical beam action.

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Behavior of self-compact reinforced concrete deep beams with small shear span to depth ratio

MATEC Web of Conferences ◽

10.1051/matecconf/201816204013 ◽

2018 ◽

Vol 162 ◽

pp. 04013

Author(s):

Hassan Hassan ◽

Mu’taz Medhlom ◽

Mohammed Hatem

Keyword(s):

Concrete Strength ◽

Experimental Program ◽

Deep Beams ◽

Shear Span ◽

Finite Element Software ◽

Strut And Tie ◽

Depth Ratio ◽

Rc Deep Beams ◽

Predicted Values ◽

Small Shear

This research is devoted to investigate the experimental and theoretical behavior of deep beams under monotonic two points loading. An experimental program examining six RC deep beams is carried out. The investigated parameters include shear span to depth ratio varying from 1.0 to 0.276. A comparative study is conducted in this paper by using finite element software ANSYS. The experimental and numerical results show that concrete strength and shear span to depth ratio are the two most important parameters in controlling the behavior of RC deep beams. Comparison of experimental results was made with corresponding predicted values using the Strut and Tie procedure presented ACI 318M-11Code and with other procedures mentioned in the literature. It was found that the Strut and Tie procedure presented in ACI 318M-11Code give conservative results as compared with the experimental tested results. The results showed reliability of analysis in predicting deep beams behavior in terms of failure load, failure mode as well as crack propagation.

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