SHEAR BEHAVIOR OF REINFORCED CONCRETE SLENDER BEAMS

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Muhammad K. Kayani ◽  
Wasim Khaliq ◽  
Muhammad K. Shehzad
Keyword(s):  
Reinforced Concrete ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Experimental Program ◽  
Longitudinal Reinforcement ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Shear Span ◽  
Depth Ratio ◽  
Slender Beams

Major factors contributing to the shear behavior in reinforced concrete (RC) beams have been identified as compressive strength of concrete, shear span to effective depth ratio, and longitudinal reinforcement. Though significant, few of these factors are not fully incorporated in ACI code provisions for design of minimum shear reinforcement. To investigate the effect of these parameters, an analytical and experimental study was undertaken on the shear behavior of ordinary strength RC slender beams with moderate longitudinal reinforcement. The experimental program consisted of testing of eight simply supported RC slender beams subjected to two concentrated loads at a shear span to depth ratio (a/d) of 2.5 and equipped with varying shear reinforcement according to four different criteria. Ultimate shear strengths obtained in this experimental program are compared to the analytical shear strengths calculated according to existing as well as proposed equations. Test results exhibit that, the modified equation proposed in this work gives more accurate prediction of shear capacity of RC beams.

Parametric Analysis of Shear Behavior of Concrete Beams Reinforced with Continuous FRP Rectangular Spirals

2012 ◽  
Vol 217-219 ◽  
pp. 2435-2439
Author(s):  
Ying Tao Li ◽  
Shi Yong Jiang ◽  
Bing Hong Li ◽  
Qian Hua Shi ◽  
Xian Qi Hu
Keyword(s):  
Parametric Analysis ◽  
Failure Modes ◽  
Shear Failure ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Reinforcement Ratio ◽  
Experimental Program ◽  
Longitudinal Reinforcement ◽  
Shear Span ◽  
Depth Ratio

An experimental program was carried out by the author to investigate the shear behavior of concrete beams reinforced with continuous FRP rectangular spirals, the main variables considered in the test were the shear reinforcement ratio and the shear span to depth ratio and the longitudinal reinforcement ratio. However, the experimental program is inadequate to gain insight into the shear behavior of the members. First, the quantities of test specimens were too small, only six beams were made and tested, the experimental database was so limited that the resultant analytical results and conclusions may not be sound enough. Second, not all the main factors that have influences on the shear behavior of the members have been treated as variables in the experimental program, such as the effective transverse compression stress and the concrete compression strength, the influences of these two factor on the shear behavior of the members were not clear yet through the experimental study. Considering the insufficient information provided by the experimental investigation, the parametric analysis of the shear behavior of the members was carried out, and a revised rotating-angle softened truss model for the shear analysis of the members was proposed as the analytical tool. Based on the proposed model, the influences of various factors on the shear capacity and shear failure modes of the members were discussed, related nonlinear analysis was carried out using the arithmetic of iteration and step approximation, and several FORTRAN codes were written accordingly. Through the experimental study and the parametric analysis, it is indicated that the shear capacity and the shear failure modes of the members are greatly influenced by three major factors, including the shear reinforcement ratio and the shear span to depth ratio and the effective transverse compression stress. The influences of the concrete compression strength and the longitudinal reinforcement ratio on the shear capacity are not noticeable comparatively. The shear capacity is little affected by the shear span to depth ratio in the case of the shear-tension failure, there is no noticeable correlation between longitudinal reinforcement ratio and the shear failure modes.

scholarly journals Shear behavior of reinforced concrete wide beams strengthened with CFRP sheet without stirrups

2019 ◽  
Vol 12 (1) ◽  
pp. 80-98
Author(s):  
Ali Laftah Abass
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Strength ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Control Beam ◽  
Cfrp Sheet ◽  
Wide Beams

Reinforced concrete wide beams (WBS) have been used in construction buildings because its provide many advantages; reducing the reinforcement congestion, reducing the quantity of the required formwork, providing simplicity for replication, and decreasing the storey height. The current study presents the results of four full-scale wide RC beams in order to study their shear behavior and investigate the effectiveness of carbon fiber reinforced polymer (CFRP) when using as shear reinforcement to improve the shear capacity of wide RC beams, one these beams was fabricated by (ANSYS) program this beam was unstrengthened with CFRP and without stirrups (control beam), the other two beams was strengthened with vertical and inclined CFRP sheet without stirrups and the last beam reinforced with shear stirrups (WBS). All beams casted with normal concrete strength (30 MPa), simply supported and under two point loads. The performances of these beams were measured in terms of; ultimate load, crack patterns, concrete and steel strains, deflection, and mode of failure. The results showed an increasing in ultimate load of strengthened beams with inclined, vertical CFRP and beam with shear reinforcement by (19.9%), (7.14%) and (39.8%) respectively as compared with the control beam, and this results means possibility of replacing the internal shear reinforcement with externally bonded CFRP.

Shear Capacity of Concrete Beams Reinforced with Continuous FRP Rectangular Spirals

2012 ◽  
Vol 204-208 ◽  
pp. 3009-3015
Author(s):  
Bing Hong Li ◽  
Shi Yong Jiang ◽  
Qian Hua Shi ◽  
Xian Qi Hu
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Concrete Beams ◽  
Point Load ◽  
Shear Capacity ◽  
Experimental Program ◽  
Arch Model ◽  
Longitudinal Reinforcement ◽  
Shear Reinforcement ◽  
Shear Span

The failure modes and the shear capacity of concrete beams reinforced with FRP reinforcement were discussed through an experimental investigation, in which continuous FRP rectangular spirals were used for shear reinforcement, while ordinary deformed steel bars are used for longitudinal reinforcement. Six concrete beams reinforced with FRP spirals were tested, the main variables considered were the shear reinforcement ratios, the shear span to depth ratios and the longitudinal reinforcement ratios. Two concrete beams of equal shear capacity which reinforced with continuous steel rectangular spirals were also tested to compare the behavior of concrete beams reinforced with different materials of spirals. All beams were tested as simply supported members subjected to a three-point load, the span of the beams varied in terms of different shear span to depth ratios. The test results show that the shear capacity and shear failure modes are greatly influenced by the shear reinforcement ratios and the shear span to depth ratios, the shear resistance provided by steel spirals is higher than that provided by FRP spirals in the case of equal shear capacity of beams, which is attributed to the differences in material properties and may result in different shear failure types. Based on the experimental program, four mechanical models are derived to give more accurate predictions of the shear capacity of test beams, the calculation results of these models are compared with that of the existing shear formulas or equations for concrete beams reinforced with FRP stirrups or spirals. The rotating-angle softened truss model, the strut-and-tie model, the shear formulas derived from the truss-arch model and Zsutty equations are suggested through comparison.

scholarly journals Analysis of fracture processes in reinforced concrete beams without stirrups

2021 ◽  
Vol 15 (57) ◽  
pp. 321-330
Author(s):  
Marta Słowik
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Load Capacity ◽  
Failure Process ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Shear Span ◽  
Depth Ratio ◽  
Slender Beams ◽  
Fracture Processes

The analysis of fracture processes which led to shear failure in reinforced concrete beams without transverse reinforcement was performed on the basis of test results from the author’s own experimental investigation and numerical simulations. The variable parameters during the experiment were a beam’s length and a shear span. It was observed that the character of failure in the beams depended on the beam’s length and the span-to-depth ratio. In slender beams characterized by the shear span-to-depth ratio 3.4 and 4.1, the formation of the critical diagonal crack caused a brittle, sudden failure and the shear capacity was low. In short beams, when the shear span-to-depth ratio was 1.8 and 2.3, the failure process had a more stable character with a slow developing of inclined cracks and the significantly higher load capacity was reached. The activation of various shear transfer mechanisms was examined with regard to the slenderness of the member and the transition between a beam action which took place in slender beams to an arch action which predominated in short beams was described.

scholarly journals Shear behavior degradation and failure pattern of reinforced concrete beam with chloride-induced stirrup corrosion

2019 ◽  
Vol 22 (14) ◽  
pp. 2998-3010 ◽  
Author(s):  
Zhao-Hui Lu ◽  
Hai Li ◽  
Wengui Li ◽  
Yan-Gang Zhao ◽  
Zhuo Tang ◽  
...  
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Shear Behavior ◽  
Reinforced Concrete Beams ◽  
Failure Pattern ◽  
Reinforcement Corrosion ◽  
Shear Span ◽  
Depth Ratio

Reinforcement corrosion exhibits an adverse effect on the shear strength of reinforced concrete structures. In order to investigate the effects of chloride-induced corrosion of reinforcing steel on the shear behavior and failure pattern of reinforced concrete beams, a total of 24 reinforced concrete beams with different concrete strength grades and arrangements of stirrups were fabricated, among which 22 beams were subjected to accelerated corrosion to achieve different degrees of reinforcement corrosion. The failure pattern, crack propagation, load–displacement response, and ultimate strength of these beams were investigated under a standard four-point loading test in this study. Extensive comparative analysis was conducted to investigate the effects of the concrete strength, shear span-to-depth ratio, and stirrup type on the shear behavior of the corroded reinforced concrete beams. The results show that increasing the stirrup yielding strength is more effective in improving the shear strength of corroded reinforced concrete beams than that of concrete compressive strength. In terms of three types of stirrups, the shear strength of the beams with deformed HRB-335 is least sensitive to stirrup corrosion, followed by the beams with smooth HPB-235 and the beams with deformed HRB-400. The effect of the different stirrups on the shear strength depends on the corrosion degree of stirrup and shear span-to-depth ratio of the beam. The predicted results of shear strength of corroded reinforced concrete beams by a proposed analytical model are well consistent with the experimental results.

scholarly journals Shear Behaviour of RC Beams Strengthened by Various Ultrahigh Performance Fibre-Reinforced Concrete Systems

2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
Walid Mansour ◽  
Bassam A. Tayeh
Keyword(s):  
Reinforced Concrete ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Element Model ◽  
Shear Behaviour ◽  
Fibre Reinforced Concrete ◽  
Rc Beams ◽  
Shear Span ◽  
Depth Ratio ◽  
Normal Strength

This study presents a numerical investigation on the shear behaviour of shear-strengthened reinforced concrete (RC) beams by using various ultrahigh performance fibre-reinforced concrete (UHPFRC) systems. The proposed 3D finite element model (FEM) was verified by comparing its results with those of experimental studies in the literature. The validated numerical model is used to analyse the crucial parameters, which are mainly related to the design of RC beams and shear-strengthened UHPFRC layers, such as the effect of shear span-to-depth ratio on the shear behaviour of the strengthened or nonstrengthened RC beams and the effect of geometry and length of UHPFRC layers. Moreover, the effect of the UHPFRC layers’ reinforcement ratio and strengthening of one longitudinal vertical face on the mechanical performance of RC beams strengthened in shear with UHPFRC layers is investigated. Results of the analysed beams show that the shear span-to-depth ratio significantly affects the shear behaviour of not only the normal-strength RC beams but also the RC beams strengthened with UHPFRC layers. However, the effect of shear span-to-depth ratio has not been considered in existing design code equations. Consequently, this study suggests two formulas to estimate the shear strength of normal-strength RC beams and UHPFRC-strengthened RC beams considering the effect of the shear span-to-depth ratio.

Predicting the effect of stirrups on shear strength of reinforced normal-strength concrete (NSC) and high-strength concrete (HSC) slender beams using artificial intelligence

2006 ◽  
Vol 33 (8) ◽  
pp. 933-944 ◽  
Author(s):  
H El Chabib ◽  
M Nehdi ◽  
A Saïd
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
High Strength ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Design Parameters ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Strength Concrete ◽  
Shear Design

The exact effect that each of the basic shear design parameters exerts on the shear capacity of reinforced concrete (RC) beams without shear reinforcement (Vc) is still unclear. Previous research on this subject often yielded contradictory results, especially for reinforced high-strength concrete (HSC) beams. Furthermore, by simply adding Vc and the contribution of stirrups Vs to calculate the ultimate shear capacity Vu, current shear design practice assumes that the addition of stirrups does not alter the effect of shear design parameters on Vc. This paper investigates the validity of such a practice. Data on 656 reinforced concrete beams were used to train an artificial neural network model to predict the shear capacity of reinforced concrete beams and evaluate the performance of several existing shear strength calculation procedures. A parametric study revealed that the effect of shear reinforcement on the shear strength of RC beams decreases at a higher reinforcement ratio. It was also observed that the concrete contribution to shear resistance, Vc, in RC beams with shear reinforcement is noticeably larger than that in beams without shear reinforcement, and therefore most current shear design procedures provide conservative predictions for the shear strength of RC beams with shear reinforcement.Key words: analysis, artificial intelligence, beam depth, compressive strength, modeling, shear span, shear strength.

Shear behavior of reinforced concrete beams strengthened in flexure with bonded carbon fibre reinforced polymers laminates

2005 ◽  
Vol 32 (5) ◽  
pp. 812-824 ◽  
Author(s):  
Francesco Bencardino ◽  
Vincenzo Colotti ◽  
Giuseppe Spadea ◽  
Ramnath Narayan Swamy
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Shear Behavior ◽  
Structural Performance ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Brittle Behavior ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

The aim of this paper is to clarify the structural performance of reinforced concrete (RC) beams with weak or without any internal shear reinforcement and externally strengthened in flexure with carbon fibre reinforced polymer (CFRP) laminates, when subjected to a shear-dominant-loading regime. Seven RC beams were specifically designed, without and with an external anchorage system, which was carefully detailed to enhance the benefits of the strengthening laminate and counteract the destructive effects of shear forces. All the beams were identical in terms of their geometry, longitudinal internal reinforcement, and concrete strength but varied, to highlight the role of shear behavior, in terms of their internal and external shear reinforcement as well as in their loading test regime. The beams were tested under four-point bending and extensively instrumented to monitor strains, deflection, cracking, load carrying capacity, and failure modes. The structural response of the tested beams has, then, been critically analyzed in terms of deformability, strength, and failure processes that occur under a shear-dominant loading regime. It is shown that with a carefully designed anchorage system, a brittle behavior without yielding of tension steel reinforcement of a flexural strengthened beam can be transformed to a less brittle behavior with yielding of tension steel reinforcement and a well-defined enhancement of structural performance in terms of both deformation and strength. The results presented in this paper should enable engineers to counteract shear failure of externally strengthened beams with little or even no internal shear reinforcement.Key words: carbon fibre reinforced polymer, shear behavior, external flexural strengthening, structural performance.

scholarly journals The influence of longitudinal reinforcement on shear capacity of reinforced concrete members without shear reinforcement

2014 ◽  
Vol 13 (3) ◽  
pp. 151-158
Author(s):  
Marta Słowik
Keyword(s):  
Reinforced Concrete ◽  
Shear Capacity ◽  
Longitudinal Reinforcement ◽  
Test Results ◽  
Shear Reinforcement ◽  
Professional Literature ◽  
Model Code ◽  
Concrete Members ◽  
Eurocode 2 ◽  
Model Code 2010

In the paper, the influence of longitudinal reinforcement on shear capacity of reinforced concrete members without shear reinforcement is discussed. The problem is analyzed on the basis of the author’s own test results and tests results reported in the professional literature. It has been concluded that longitudinal reinforcement has an effect on shear capacity especially in members of shear span-to-depth ratio a/d < 2,5. The test results have also been used to verify standard methods of calculating the shear capacity in reinforced concrete members without shear reinforcement given in Eurocode 2, ACI Standard 318 and Model Code 2010.

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