AN EXPERIMENTAL INVESTIGATION INTO SHEAR

Heliyon, 2021

The shear behavior of reinforced concrete (RC) beams has been a major research area for a long time. Since the shear response of RC beams is affected by different factors, many researchers have reported that the nature of shear behavior is complicated. One of these factors worth investigating is the inclination of shear reinforcements. This paper investigated the effect of the orientation of stirrups on the shear capacity of RC beams as the shearspan-to-depth ratio (a/d) varies. The contribution of concrete compressive strength was also studied. An experimental program investigating 21 RC beams has been conducted. The test results revealed that the shear capacity increases as the arrangement of stirrup changes from conventional vertical arrangement to inclined arrangement. However, the increment is high in beams with (a/d) ratio of 2.2 than beams with (a/d) ratio of 2.6, which are relatively slender. Shear capacity also increases as concrete compressive strength increase, which shows that concrete contribution to the shear capacity of beams should be taken in to account. In addition to the experimental test, the beams were analyzed numerically by using a general-purpose finite element package, Abaqus. The shear capacity of reinforced concrete beams obtained from the numerical analysis is in a good agreement with the experimental result. The results obtained by numerical analysis and experimental tests are compared to analytically calculated values by using shear provisions of ACI 318-14 and EN-2. Both ACI 318-14 and EN-2 are generally conservative in predicting the shear capacity of RC beams. However, the conservativeness of these codes reduced as a/d ratio of the beams increase.

Maǧallaẗ al-handasaẗ wa-al-tiknūlūǧiyā, 2016

High-performance fiber-reinforced concrete is a new class of concrete that has been developed in recent decades. It exhibits enhanced properties such as high compressive strength and improved tensile strength. Three types of concrete with different compressive strengths, namely, normal-strength concrete, high-strength concrete, and high-performance concrete, were used in this study. The experimental program included casting and testing sixteen reinforced concrete deep beams without stirrups to study the shear strength and behavior of these beams under two-point loading. The variables considered were the compressive strength of concrete (f′ c) (40-120 MPa), shear span-to-depth ratio (1, 1.5, 2, 2.5, and 3), and the ratio of the amount of flexural steel bar ratio (1.35%, 2.40%, 3.76%, and 6.108%). Experimental results showed that increasing concrete compressive strength and flexural steel bar ratio increased ultimate shear capacity. By contrast, increasing shear span-to-depth ratio and span-to-depth ratio reduced ultimate shear capacity. Based on the test results of this investigation (16 beams) and those of available literature (233 deep beams), an equation that considered the parameters affecting shear stress (f′ c , l/d, a/d, and w) was proposed using SPSS software. The proposed equation was compared with predictions made by the American Concrete Institute (ACI) and the works of other researchers, including that of Zsutty and Aziz. The ACI predictions were conservative and the proposed equation had a lower coefficient of variation.

ACI Structural Journal, 2011

This paper presents the results of an investigation of shear strength of large-sized concrete beams reinforced with ASTM A1035 Grade 100 bars. The performance of these beams is compared to that of similar beams reinforced with ASTM A615 Grade 60 bars. The results indicate that by using the higher yield strength of ASTM A1035 bars with a reduced reinforcement ratio, the beams can achieve similar shear strengths as the beams reinforced with Grade 60 bars. The results also show that cracking and deflection under service load of the beams with a reduced reinforcement ratio are within acceptable limits.

2019

Initial design errors, especially installation of stirrup, one of them can cause the beam having shear failure due to installed capacity of stirrup less than the shear capacity that occurs. Shear strengthening in this study used externally stirrup ∅6-75 which were install in the shear area only. The results of calculation analysis, shear capacity can increased up to 137.82%; 133.42% and 137.12%.. When viewed from the deflection that occurred during the first crack, the reinstrengthd beam experienced a relatively smaller deflection of 0.61 mm beam; 0.31 mm and 0.18 mm rather than beams without externally stirrup 1.28 mm; 0.55 mm and 0.32 mm, so that the beam with externally stirrup can be said to be more rigid than the beam without externally stirrup.

ACI Structural Journal, 1990

This paper deals with the analysis of the shear strength of reinforced concrete elements, with loads on the upper side near edge of the support. The reinforced concrete elements are designed according to EN 1992-1-1:2004. Results of the calculated shear strength are compared with the results of the experimental research of the reinforced concrete beams that were made of highstrength concrete and normal-strength concrete, comparatively. Analysis is related to the beams for which ratio between shear span (a v), measured from the inner edge of the support, and effective depth of the cross-section (d), is smaller than 2.0. In that case, for design of the shear strength according to EN 1992-1-1:2004, provision that shear force should be reduced by the v /2d is prescribed. Results of the experimental research, in correlation with shear strength calculated according to EN 1992-1-1:2004, are being analyzed in this paper. It has been established that the proposed reduction gives a significantly reduced magnitude of the design value of the load, which do not provide the necessary safety of calculation.

2016

This paper presents the test results of experimental study on shear strength of reinforced concrete beams without stirrups. The test variables in this study were type of beam cross section and ratio of longitudinal reinforcement. Six simple supported beams, consisting of three beams with rectangular cross section and three beams with T section, subjected to two point load were tested until failure. During the test, the values of the diagonal crack load and the maximum load were observed as well as the deformation of the beams. Existing empirical equations for shear strength of concrete presented in the literature and design codes were used and then compared to that value obtained from the test. Comparison between test results and theoretical shear capacity show that all of equations conservatively estimate the occurrence of shear failure with the values of the test results 10 to 90% higher than the theoretical values. It was confirmed from the test that the shear capacity of T-beams...

International Journal of Engineering and Technology, 2013

This study presents test results of simply supported concrete beams longitudinally reinforced either by steel or glass fiber-reinforced polymer (GFRP). A total of sixteen large-scale concrete beams with steel stirrups were constructed and tested under four-point monotonic loading until failure. Half of the beams were longitudinally reinforced with GFRP bars, while the other half was reinforced with conventional steel bars as control specimens. To examine the shear behavior of the GFRP reinforced concrete (RC) beams, the main parameters investigated in the study included shear span-effective depth ratios, longitudinal reinforcement ratios and stirrup ratios. Two modes of failure, namely flexure and shear were observed. Due to low modulus elasticity of FRP bars, it was found that lesser shear strength resulted in concrete beams reinforced with GFRP bars compared to beams reinforced with steel bars. Moreover, the influence of the shear span-effective depth ratios and longitudinal reinforcement ratios significantly affect the distribution of internal forces in GFRP reinforced concrete beams. The test results correlated well with the prediction values provided by standard codes and design guidelines except in the case of GFRP reinforced concrete beams failed on shear.

New Solutions for our Society (Abstracts Book 314 pages + CD-ROM full papers 1196 pages), 2008

Concrete beams may fail in shear depending on kind of loading and amount of shear reinforcement. A research project has been started to investigate a new method of strengthening beams with insufficient shear resistance by applying post-installed reinforcement and in parallel derive an adequate model for shear design. Number and location of the inclined rebars as well as type of injection mortar has been varied. The rebars were installed in mortar-injected boreholes and anchored with metal plates at the accessible bar end. The test results confirmed that post-installed rebars can significantly increase the beam shear resistance provided they are situated properly and adequate injection mortars used. Above that the evaluation of the different contributions to shear resistance like truss action, dowel action and shear strength of compression chord provides new findings on the general shear failure mechanism in RC structures.

IOP Conference Series: Earth and Environmental Science, 2020

Concrete is a brittle material and respectively weak in tensile strength and tensile strain. Concrete technology is applied at which concrete is reinforced with steel fibre, as known as steel fibre reinforced concrete (SFRC) to produce a versatile structural material to exhibit superior strength properties in terms of ductility, fracture energy, toughness, strength and durability. The introduction of short, discontinuous and randomly oriented steel fibres into conventional concrete mixes possesses a strong bond with the concrete matrix with high elastic modulus. The goal of this study is to create a standard foresight in determining the potentiality of steel fibre as secondary shear reinforcement to partially or fully replace shear stirrups in conventional concrete. For this purpose, the series of SFRC beam specimens without stirrups which have the same concrete mixing ratios were produced with the inclusion of 0.6 % and 0.7 % steel fibre by volume fractions and compared with conven...

International Journal of Advance Research and Innovative Ideas in Education, 2017

Shear capacity of the reinforced concrete beam depends upon various parameters. On the basis of different parameters, ample studies have been done to assured the authentic deportment of shear failure. Though ample studies carried out on shear failure of concrete beam still it is controversial regarding the exact shear behaviour of reinforced cement concrete structure elements. In this work the comparative study of reinforced concrete beams having no shear reinforcement by utilizing different design approaches like ACI, Canadian, IS Code, CEP-FIP Model, Zsutty equation and Bazant equation. An attempt has been made to study shear strength of concrete beams with various shear span to depth ratios (a/d = 1, 2 & 3) and different longitudinal steel ratios with no shear reinforcement and compare the experimental results with the available shear models. Six shear models for comparison are considered namely, ACI Code, Canadian Code, IS Code, CEP-FIP Model, Zsutty equation and Bazant equation...