scholarly journals Experimental Evaluation on Components of Shear resistance of Reinforced Concrete Beams with Shear Reinforcement Provided

2021 ◽  
Author(s):  
Sreenivasa Prasad Joshi ◽  
Poluraju P
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Shear Resistance ◽  
Transfer Mechanism ◽  
Reinforced Concrete Beams ◽  
Structural Behavior ◽  
Compression Zone ◽  
Shear Reinforcement ◽  
Shear Transfer ◽  
Aggregate Interlocking

Abstract The contribution of aggregate interlocking and dowel force in shear strength of reinforced concrete beams was topic of research for many years. The precise forecasts of shear behavior were challenging to determine due to complication involved. The existing theories had focused on aggregate interlocking force and shear resistance arising due to concrete compression zone, neglecting the contribution of dowel force despite considering as significant constituent in shear transfer mechanism. The present investigation focuses on cogitating all components in shear transfer mechanism by providing shear reinforcement and keeping clear cover and effective span to depth ratio constant. Sixteen specimens were considered for parametric study by employing suitable variables such as increase in strength of concrete and variation in flexural reinforcement. Eight specimens were conventional beams and the remaining eight specimens were provided with preformed cracks. Moment vs. displacement curvature and strain vs. moment curvature were plotted to evaluate shear at uncracked compression zone and accordingly aggregate interlocking force and dowel force were determined based on the empirical formulas proposed. From the result it was confirmed that contribution of aggregate interlocking force and dowel force were insignificant and shear resistance due to uncracked compression zone is the sole contributor in shear transfer mechanism. Structural behavior of concrete beams was also studied and it was confirmed that beams with preformed cracks exhibited better structural behavior when related to conventional beams.

scholarly journals Shear resistance of welded inclined bars in rectangular reinforced concrete beams

2018 ◽  
Vol 250 ◽  
pp. 03003
Author(s):  
Noor Suhaida Galip ◽  
Roslli Noor Mohamed ◽  
Ramli Abdullah
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Beams ◽  
Shear Resistance ◽  
Reinforced Concrete Beams ◽  
Shear Reinforcement ◽  
Shear Forces ◽  
Distance Ratio ◽  
Effective System ◽  
Horizontal Portion

The bent-up bars have not been used as shear reinforcement in beams since the past 40 years or so. In all cases of design and construction nowadays, shear forces are resisted by vertical links only. Some complications in installing the multiple set of bent-up bars, the less opportunity to have sufficient number of bent-up bars due to small number of flexural reinforcement provided at the mid-span of the beams and also the large anchorage required for the horizontal portion of the bars beyond the upper end of the bend could be the reasons behind this. This paper presents the results of tests on five rectangular reinforced concrete beams in which the effectiveness of welded inclined bars (WIB) as shear reinforcement was studied. Two of the beams were controlled specimens, with no shear reinforcement in one, and full design vertical links in another. The other three beams were provided with three different quantities of WIB, measured in terms of area to distance ratio, Asw / S as shear reinforcement in the shear spans. All beams were tested to failure under two point loads with a shear span to effective depth ratio of 2.34, which would ensure that the failure was due to shear unless their shear capacities were larger than the flexural capacity. The performances of the beams were measured in terms of deflection, crack formation, strains in WIB and on the concrete surfaces in the shear region, ultimate loads and failure modes. The results show that WIB alone is capable of carrying the whole shear forces in the beam, and larger shear capacities are achieved with a larger quantity of WIB, and a higher grade of the bars used. The beam with WIB requires 22% less in the quantity of Asw / S compared to that with vertical links to achieve the same shear resistance. These suggest that WIB can be used as an effective system of shear reinforcement in beams.

Mechanism of shear transfer in reinforced concrete beams

1977 ◽  
Vol 4 (2) ◽  
pp. 145-152
Author(s):  
K. N. Smith ◽  
S. M. Fereig
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Measurement Data ◽  
Reinforced Concrete Beams ◽  
Compression Zone ◽  
Interface Shear ◽  
Small Component ◽  
Shear Transfer ◽  
Dowel Action ◽  
Web Reinforcement

The mechanism of shear transfer in reinforced concrete beams with short shear spans is investigated with a view to defining the relative contribution of various component actions such as interface shear transfer across the characteristic inclined crack in such members, shear transferred by the uncracked compression zone, dowel action by the longitudinal tension reinforcement, and the contribution of the web reinforcement. The members tested and analyzed have a shear span to depth ratio of 1.5 and were loaded in the common framing situation involving shear on the sides of the members.For the beams either with horizontal web reinforcement or without any web reinforcement the distribution of internal forces was similar, with interface shear transfer, dowel action, and shear carried by the compression zone contributing to the capacity. In the case of members for which vertical web reinforcement was provided, interface shear transfer and dowel action were decreased to comparatively small component actions in the system. Acquisition of extensive measurement data and analysis of the behaviour history through various stages of loading permit the mechanism of shear transfer to be quantitatively defined.

scholarly journals Shear Performance of Steel Fibers in Reinforced Concrete Beams

2019 ◽  
Vol 9 (2) ◽  
pp. 345-350
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Resistance Mechanism ◽  
Shear Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Experimental Program ◽  
Shear Reinforcement ◽  
Shear Span

Over the past few decades, a significant growth was observed on utilization of steel fibers in Reinforced Concrete (R.C) members. Past research studies on hybrid concrete endorsed optimum utilization of steel fibers (1.5% by volume) as it effectively contributed to improve flexural properties of reinforced concrete members such as R.C beams and slabs .But the contribution of fibers against shear resistance mechanism of R.C beams are not identified well in the previous research. In this context an experimental program was conducted to find Shear contribution and associated Parameters of fibers in the Steel Fiber Reinforced Concrete (SFRC) beams. A series of test programmes are conducted on three full scale reinforced concrete beams (NSF: No steel fibers, BSF1: Steel fibers in shear span, BSF2: Steel fibers in full span) with different configuration of shear reinforcement by using varied range of SFRC in the tested beam. The test results evaluated on the basis of strength and durability aspects at service loads and limit of failure conditions. The results concluded that the presence of steel fibers in reinforced concrete beam significantly contributed to induce shear resistance mechanism and ductile property of R.C beam. This improvement observed in BSF2, when the SFRC constituted in shear span region and the rest of R.C beam arranged with minimum conventional stirrups as shear reinforcement. Further the steel fibers possess good compatibility with concrete and steel reinforcement ,which enhance mechanical and serviceability conditions of R.C beam such as shear strength, ductility, stiffness with respect to strength and deflection, crack width during serviceability conditions of the beam.

scholarly journals Influence of coarse aggregate on the shear strength of reinforced concrete beams

2020 ◽  
Author(s):  
◽  
Hoosen Ahmed Jajbhay
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Shear Reinforcement ◽  
Shear Transfer ◽  
Coarse Aggregates

Research to accurately predict the shear capacity of reinforced concrete beams without shear reinforcement has been ongoing since the early 20th century. Aggregate interlock of the coarse aggregates at the shear crack interface is one of the internal mechanisms of shear transfer and a major contributor to the shear capacity of slender beams. It is plausible, therefore, to investigate if the coarse aggregate itself influences the shear capacity of a concrete beam. The influence of the type of coarse aggregate on the shear capacity of beams without shear reinforcement was investigated in this study. From the literature study an understanding of the properties of coarse aggregates was gained, the internal mechanisms of shear transfer in reinforced concrete beams without shear reinforcement were determined, and the parameters influencing shear strength were identified. Based on this information an experimental program was designed. Eighteen reinforced concrete beams without shear reinforcement were cast. The beams were cast from three different types of coarse aggregates commonly used in the Durban area, i.e., dolerite, quartzite and tillite. For each type of coarse aggregate two variations were tested, i.e., 13 mm and 19 mm maximum aggregate sizes. For each size of coarse aggregate, three concrete strengths were tested. The beams were loaded in a beam press, by applying an increasing point load offset from midspan to induce cracking on the shorter side, until shear failure of the beam occurred. For the three concrete strengths, beams cast from dolerite had the highest shear capacity while beams cast from tillite had less shear capacity than beams cast from quartzite coarse aggregate. Furthermore, beams cast from 13 mm maximum size coarse aggregate had higher shear capacity than beams cast from 19 mm aggregate. The conclusion may be drawn that the type and size of coarse aggregate does influence the shear strength of a reinforced concrete beam without shear reinforcement.

Assessment of the Model Uncertainty in Shear Resistance of Reinforced Concrete Beams without Shear Reinforcement / Hodnocení Modelové Nejistoty Pro Smykovou Odolnost Železobetonových Nosníků Bez Smykové Výztuže

2012 ◽  
Vol 12 (2) ◽  
pp. 195-204 ◽  
Author(s):  
Miroslav Sýkora ◽  
Milan Holický
Keyword(s):  
Reinforced Concrete ◽  
Model Uncertainty ◽  
Concrete Beams ◽  
Shear Resistance ◽  
Mean Value ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Shear Reinforcement ◽  
Probabilistic Description ◽  
The Mean

Abstract The paper is focused on the model uncertainty related to shear resistance of reinforced concrete beams without special shear reinforcement considering available test results. Variation of the model uncertainty with basic variables is analysed and significant variables are identified for the section-oriented formula provided in EN 1992-1-1. Proposed probabilistic description of the model uncertainty consists of the lognormal distribution having the coefficient of variation of 0.15 and the mean value varying from 0.9 to 1.05 for beams with light to heavy longitudinal reinforcement.

SHEAR CAPACITY EVALUATION OF REINFORCED CONCRETE BEAMS: FINITE ELEMENT SIMULATION

2015 ◽  
Vol 77 (16) ◽  
Author(s):  
Mohammadamin Azimi ◽  
Mohanadoss Ponraj ◽  
Asma Bagherpourhamedani ◽  
Mahmood Md. Tahir ◽  
Sk Muiz Sk Abd. Razak ◽  
...  
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Shear Resistance ◽  
Reinforced Concrete Beams ◽  
Shear Behaviour ◽  
Shear Reinforcement ◽  
Continuous Shear ◽  
Resistance System ◽  
Shear Performance

The shear performance of reinforced concrete beams with rectangle cross-section and two different continuous rectangular spiral shear reinforcement under monotonous loading is numerically evaluated. Further, the behaviour of two continuous shear reinforcement systems named, “Single Square Spring Shear Resistance System” (SSSSRS) and “Double Square Spring Shear Resistance System” (DSSSRS) as transverse reinforcements are compared with conventional discontinuous system “Stirrups”. The finite element study includes three (3) beams. The results clearly show that the application of continuous shear reinforcement system delivered improved shear behaviour and enhanced bearing capacity in beams. Beams with Single Square Spring Shear Resistance System (SSSSRS) and Double Square Spring Shear Resistance System (DSSSRS) exhibited 14.4% and 19.8% increased shear performance in comparison with conventional control beam. It was concluded that under the same deflection higher forces was achieved for “Single Square Spring Shear Resistance System” (SSSSRS) and “Double Square Spring Shear Resistance System” (DSSSRS) compared to control specimens.

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