Shear Strength Of Beams Research Articles

Machine Learning-Based Models for Shear Strength Prediction of UHPFRC Beams

Estimating shear strength is a crucial aspect of beam design. The goal of this research is to develop a shear strength calculation technique for ultra-high performance fiber reinforced concrete (UHPFRC) beams. To begin, a shear test database of 200 UHPFRC beam specimens is established. Then, random forest (RF) is used to evaluate the importance of influence factors for the shear strength of UHPFRC beams. Subsequently, three machine learning (ML)-based models, including artificial neural network (ANN), support vector regression (SVR), and eXtreme-gradient boosting (XGBoost), are proposed to compute shear strength. Results demonstrate that the area of longitudinal reinforcement has the greatest influence on the shear capacity of UHPFRC beams, and ten parameters with high importance (e.g., the area of longitudinal reinforcement, the stirrup strength, the cross-section area, the shear span ratio, fiber volume fraction, etc.) are selected as input parameters. The models of ANN, SVR, and XGBoost have close accuracy, and their R2 are 0.8825, 0.9016, and 0.8839, respectively, which are much larger than those of existing theoretical models. In addition, the average ratios of prediction values of ANN, SVR, and XGBoost models to experimental results are 1.08, 1.02, and 1.10, respectively; the coefficients of variation are 0.28, 0.21, and 0.28, respectively. The SVR model has the best accuracy and reliability. The accuracy and reliability of ML-based models are much better than those of existing models for calculating the shear strength of UHPFRC beams.

Machine Learning-Based Model for Predicting the Shear Strength of Slender Reinforced Concrete Beams without Stirrups

The influence of concrete mix properties on the shear strength of slender structured concrete beams without stirrups (SRCB-WS) is a widespread point of contention. Over the past six decades, the shear strength of SRCB-WS has been studied extensively in both experimental and theoretical contexts. The most recent version of the ACI 318-19 building code requirements updated the shear strength equation for SRCB-WS by factoring in the macroeconomic factors and the contribution of the longitudinal steel structural ratio. However, the updated equation still does not consider the effect of the shear span ratio (a/d) and the yield stress of longitudinal steel rebars (Fy). Therefore, this study investigates the importance of the most significant potential variables on the shear strength of SRCB-WS to help develop a gene expression-based model to estimate the shear strength of SRCB-WS. A database of 784 specimens was used from the literature for training and testing the proposed gene expression algorithm for forecasting the shear strength of SRCB-WS. The collected datasets are comprehensive, wherein all considered concrete properties were considered over the previous 68 years. The performance of the suggested algorithm versus the ACI 318-19 equation was statistically evaluated using various measures, such as root mean square error, mean absolute error, mean absolute percentage error, and the coefficient of determination. The evaluation results revealed the superior performance of the proposed model over the current ACI 318-19 equation. In addition, the proposed model is more comprehensive and considers additional variables, including the effect of the shear span ratio and the yield stress of longitudinal steel rebars. The developed model reflects the power of employing gene expression algorithms to design reinforced concrete elements with high accuracy.

Shear strength of reinforced concrete flexural members without web reinforcement in compliance with mechanical analysis

Reinforced concrete (RC) beams are important components and critical bearing members in concrete structures. Owing to the complexity of shear behavior for RC beams, most current design approaches to predict shear capacity are highly empirical, which cannot physically explain the shear failure mechanism and, consequently, should only be used within the bounds of the testing regimes from which they were derived. To accommodate this issue, a mechanics-based shear model, which can explain the physical process of shear failure mechanism with a clear physical meaning, was established to quantify the shear capacity of RC beams without stirrups with any type of longitudinal reinforcement and concrete. In this study, the force on each part of the critical failure diagonal crack plane of the RC beams without web reinforcement was analyzed, and the variation of sliding strength with any given inclination angle of diagonal crack was derived. Furthermore, the inclination angle of the critical diagonal crack along which failure occurs with the shear-span ratio was determined by the correlation analysis. The model was validated using 9 test specimens with steel longitudinal reinforcement performed in this study, with a further 452 published shear tests of FRP-reinforced beams without web reinforcement. In addition, the selected design codes and available models were used to calculate the shear strength of test beams. The comparison result shows that a reduction to different degrees in both the mean and scatter of the ratio of the experimental-versus-predicted shear capacity result for the proposed mechanics-based model. Meanwhile, the proposed model can accurately reflect the influence of the main shear parameters, and the prediction accuracy shows no obvious correlation with the wide range variation of these shear parameters.

Shear strength of eco-friendly self-compacting concrete beams containing ground granulated blast furnace slag and fly ash as cement replacement

It is becoming essential to find solutions to preserve the environment from emissions related to cement manufacture. One of the most effective solutions and techniques is using supplementary cementitious materials (SCMs) as cement substitutes to produce eco-friendly concrete. This experimental work primarily aimed to investigate the impact of ground granulated blast furnace slag (GGBFS) and fly ash (FA) as cement substitutes on the shear behavior of SCC beams. Six SCC mixtures with binary and ternary binders based on cement, FA, and GGBFS were manufactured. Twelve SCC beams (two beams for each mixture) with and without shear reinforcement were cast and tested under simply supported four-point loading conditions. Test variables were different substitute levels of GGBFS and FA (0 %, 25 %, and 50 %) of the total weight of cement and shear reinforcement ratio. The findings indicated that the addition of GGBFS and FA had a negative impact on the mechanical characteristics of SCC. The stiffness, ultimate shear strength, and toughness of SCC beams decrease with the increase of GGBFS and FA contents. The ultimate shear strength of tested beams without stirrups comprising GGBFS and FA up to 50 % was reduced by about 12.1 % and 19.3 %, respectively. The ultimate shear strength, shear ductility, and stiffness of tested beams comprising up to 50 % GGBFS were reduced by about 10.5 %, 36.4 %, and 9.1 %, respectively. Based on the experimental results, from both an environmental and engineering perspective, a combination of ternary binders based on 50 % cement, 25 % FA and 25 % GGBFS can be considered the optimum substitute ratios that can be used on the SCC mixture. Whereas it contains a high level of SCMs causing a minimal impact on shear strength with the improvement of the ductility of SCC beam. Lastly, the experimental ultimate shear strength of test specimens was compared with those predicted from different international design codes.

Composite Structural Supercapacitors: High-Performance Carbon Nanotube Supercapacitors through Ionic Liquid Localisation.

Composite structural supercapacitors (SSC) are an attractive technology for aerospace vehicles; however, maintaining strength whilst adding energy storage to composite structures has been difficult. Here, SSCs were manufactured using aerospace-grade composite materials and CNT mat electrodes. A new design methodology was explored where the supercapacitor electrolyte was localised within the composite structure, achieving good electrochemical performance within the active region, whilst maintaining excellent mechanical performance elsewhere. The morphologies of these localised SSC designs were characterised with synchrotron X-ray fluorescence microscopy and synchrotron X-ray micro-computed tomography and could be directly correlated with both electrochemical and mechanical performance. One configuration used an ionogel with an ionic liquid (IL) electrolyte, which assisted localisation and achieved 2640 mW h kg−1 at 8.37 W kg−1 with a corresponding short beam shear (SBS) strength of 71.5 MPa in the active area. A separate configuration with only IL electrolyte achieved 758 mW h kg−1 at 7.87 W kg−1 with SBS strength of 106 MPa in the active area. Both configurations provide a combined energy and strength superior to results previously reported in the literature for composite SSCs.

Machine-learning-aided improvement of mechanics-based code-conforming shear capacity equation for RC elements with stirrups

The development of shear capacity equations for reinforced concrete (RC) beams and columns has been historically pursued starting from the conceptualization of a resisting mechanism. Recently, machine learning techniques are attracting more and more interest in this field. Mechanics-based and data-driven approaches (i.e., white box and black box modeling, respectively) have been considered independently so far. Conversely, this work aims at exploring a hybrid alternative way (i.e., gray box modeling) for deriving the shear capacity equation for RC beams and columns, in which a mechanics-based code-conforming formulation is improved thanks to a machine-learning-aided approach. Specifically, the capacity equation currently in use within Europe that relies on the variable-angle truss resisting mechanism is enriched by means of Genetic Programming. Easy-to-use novel expressions for the two fundamental coefficients ruling the concrete contribution are defined to better match experimental data. The performance of the newly obtained equation is first discussed within the largest comparative assessment ever presented so far among shear strength formulations reported into existing technical codes around the world. Afterward, it is recast into a code-formatted design capacity equation using a simple, yet reliable, procedure. Overall, the results demonstrate that merging mechanics-based and data-driven methods can be beneficial in the development of capacity equations since it allows preserving the physical meaning of the resisting mechanism while enhancing the accuracy of the final predictions by means of machine learning techniques. Although the methodology is here applied to evaluate the shear strength of RC beams and columns, it is very general and can be readily extended to the development of further capacity equations.

A novel shear strength model for partially encased composite (PEC) beams based on strain compatibility

Steel and concrete composite beam has been widely applied in large-span or heavily-loaded structures; however, the large shear force at the beam supports may cause web crippling or local damage. To address this problem, partially encased composite (PEC) beams, in which steel web is encased in concrete or reinforced concrete, are proposed to enhance the load-carrying capacity, anti-crippling, and anti-fire performances. In engineering practice, the vertical shear usually governs the final failure at intermediate supports; hence, accurate shear strength prediction is essential for PEC beams in practical design. Although some existing test results and shear equations exist for shear-critical PEC beams, the shear mechanism is still unclear because two shear force transferring mechanisms are coupled by the structural steel and web concrete. Therefore, it is essential to explore the contributions of the different mechanisms and how they work together as a composite structure. In this paper, the shear strength equations in current design codes and the shear strength models proposed by other researchers were reviewed and evaluated using a database consisted of the existing test results of 27 large-scale PEC beams. After identifying the shortcomings of these equations and models, this paper proposed a novel shear strength model, in which the shear contributions of the structural steel and web concrete were determined by von Mises yielding law and composite truss analogy, and the interaction between these two parts was evaluated by the strain compatibility. Finally, a comparison with the database was reported to verify the applicability of the proposed model. The results indicated that the proposed model could predict the shear strength of PEC beams with sufficient accuracy, and the strain compatibility could reasonably decouple the shear contributions of different anti-shear mechanisms.

Shear Strength of Ultra-High-Performance Concrete (UHPC) Beams without Transverse Reinforcement: Prediction Models and Test Data.

The use of Ultra-High-Performance Concrete (UHPC) in beams has been growing rapidly in the past two decades due to its superior mechanical and durability properties compared to conventional concrete. One of the areas of interest to designers is the elimination of transverse reinforcement as it simplifies beam fabrication/construction and could result in smaller and lighter beams. UHPC has a relatively high post-cracking tensile strength due to the presence of steel fibers, which enhance its shear strength and eliminate the need for transverse reinforcement. In this paper, UHPC shear test data were collected from the literature to study the effect of the following parameters on the shear strength of UHPC beams without transverse reinforcement: compressive strength, tensile strength, level of prestressing, longitudinal reinforcement ratio, and fiber volume fraction. Statistical analysis of test data indicated that level of prestressing and tensile strength are the most significant parameters for prestressed UHPC beams, whereas longitudinal reinforcement ratio and tensile strength are the most significant parameters for non-prestressed UHPC beams. Additionally, shear strength of the tested UHPC beams was predicted using five models: RILEM TC 162-TDF, 2003, fib Model Code, 2010, French Standard NF P 18-710, 2016, PCI-UHPC Structures Design Guide, 2021, and Draft of AASHTO Guide Specification for Structural Design with UHPC, 2021. Comparing measured against predicted shear strength indicated that the French Standard model provides the closest prediction with the least scatter, where the average measured-to-predicted strength was 1.1 with a standard deviation of 0.38. The Draft of AASHTO provided the second closest prediction where the average measured-to-predicted strength was 1.3 with a standard deviation of 0.64. The other three models underestimated the shear strength.

Shear Resistance of Fibrous Reinforced Concrete Deep Beams with Opening – A Critical Review

Reinforced concrete deep beams are more prone to shear failure. Thus, it is important to study the shear behavior for structural reinforcements. The presence of web openings in reinforced concrete deep beams is frequently required to provide accessibility such as doors and windows or to accommodate essential services such as ventilating and air conditioning ducts that affect the shear resistance. This research highlights the limited research on the shear resistance of fibrous reinforced concrete deep beams containing openings worldwide and illustrates their influence on shear behavior. This review has shown that the ultimate and the first cracking loads increase, increasing steel fiber content to a certain limit. End hooked steel fiber with 1.5% gave the highest shear resistance and ultimate load capacity compared with other types of steel fiber. Moreover, the stiffness of reinforced concrete deep beams increased with increasing fiber content from 0 to 1.5%. In addition, the effect of web openings on the shear strength of deep beams at the ultimate and cracking loads depends on the degree of interruption of the natural load path joining the loading.

RC beams retrofitted by FRP oriented in any direction: Influence of the effectiveness factors

Shear strength of FRP-retrofitted RC beams is usually influenced by different brittle failure modes characterizing the collapse of the FRP reinforcement. The most significant analytical models for assessing the shear strength of FRP-retrofitted RC beams reflect the effect of brittle failure through an effectiveness factor “R”, which reduces the ultimate tensile strength of FRP. The brittle collapse of FRP reinforcement often leads to a lower shear contribution by steel stirrups due to hindering of the yielding of all stirrups involved by critical cracking. Some analytical models consider this phenomenon introducing a further effectiveness factor “r”, which reduces the yielding strength of stirrups. The key differences characterizing many of the shear models are represented by the expressions used for assessment of the effectiveness factors. This paper focuses on the influence of effectiveness factor models in analytical predictions provided by different shear models. The reduction of the shear contribution of steel stirrups due to FRP brittle failure is modeled as dependent on the FRP wrapping scheme, through the ratio between FRP effective strain and steel yielding strain. To highlight the influence of the effectiveness factor for steel stirrups, two analyses are performed through different shear models, considering the effectiveness factor for FRP only, and considering the effectiveness factor for both FRP reinforcement and steel stirrups. The results are discussed considering two databases, one constituted by beams whose FRP reinforcement and steel stirrups are arranged at right angles to the beam axis, and one in which the FRP is arranged at angles different from 90°.

Assessing the shear behavior of corroded steel fiber reinforced concrete beams without shear reinforcement using nonlinear finite element analysis

The shear behavior of steel fiber reinforced concrete (SFRC) beams has been assessed in a large number of previous studies. However, the shear strength of corroded SFRC beams without shear reinforcement is still an unresolved topic. In this paper, the finite element models of non-corroded and corroded SFRC beams have been constructed and verified regarding load-displacement curves, crack patterns, and failure modes. Finally, a parametric study also was performed to assess the effect of essential design parameters on the shear strength of SFRC beams under corrosion attacks. The results show that the reinforcement corrosion degree and concrete compressive strength are the most influencing parameters on the shear strength of SFRC beams, followed by the shear span-to-depth ratio and the steel-reinforced ratio.

Influence of Cross-Section Shape and FRP Reinforcement Layout on Shear Capacity of Strengthened RC Beams.

The evaluation of the shear capacity of an FRP-strengthened reinforced-concrete beam is challenging due to the complex interaction between different contributions provided by the concrete, steel stirrup and FRP reinforcement. The shape of the beam and the FRP inclination can have paramount importance that is not often recognized by the models that are suggested by codes. The interaction among different resisting mechanisms has a significant effect on the shear capacity of beams, since it can cause a reduction in the efficiency of some resisting mechanisms. A comparative study of the performance in the shear resistance assessment provided by three models with six different effectiveness factors (R) is performed, considering different cross-section shapes, FRP wrapping schemes, inclination and anchorage systems. The results revealed that the cross-section shape, the FRP inclination and the efficiency of the FRP anchorages have a significant effect on the shear strength of beams. The analysis results show that the three models are able to provide an accurate average estimation of shear strength (but with a coefficient of variation up to 0.35) when FRP reinforcement orthogonal to the beam axis is considered, while a significant underestimation (up to 19%) affected the results for inclined FRP reinforcement. Moreover, all the models underestimated the resistance of beams with a T section.

Effect of Web Reinforcement on Shear Strength of Deep Beams and Crack Propagation

Effect of Web Reinforcement on Shear Strength of Deep Beams and Crack Propagation

Flange Contribution to the Shear Strength of RC T-Beams with Flange in Compression

As is well known, in the current design codes, the shear strength of beams is calculated based on the modified truss theory, which does not consider the effects of the flange area of T-beams. The main objective of this paper was to gain a better understanding and enhance the experimental database of the shear behavior of RC T-beams and illustrate the contribution of the flange to the shear capacity of T-beams. To accomplish this aim, a specially designed experimental program was executed, and its test results were analyzed. The main investigated variables were flange dimensions (thickness and width) and its reinforcement (longitudinal and/or vertical). Nineteen simply supported beam specimens were tested to failure under a load configuration made of two concentrated loads. Eighteen specimens had T-shaped cross-sections, while one specimen had a rectangular cross-section for comparison purposes. The items monitored during testing included the development of diagonal cracks, concrete strains, reinforcement strains, maximum loads, and deflections. Test results showed a notable increase in the shear strength of T-beams compared to rectangular beams with the same web size. For the range of variables investigated, increasing the flange thickness-to-beam depth ratio (ρt) from 0.3 to 0.5 increased the shear capacity by up to 54%. In addition, increasing the flange width-to-web width ratio (ρb) from 3 to 5 increased the shear capacity by up to 19%. It was also shown that the results of three-dimensional finite element (FE) analyses using ANSYS compared reasonably well with the test results for all specimens. Finally, based on the test and FE results, a simplified method that accounts for the contribution of the flange to shear capacity was proposed.

Contribution of Longitudinal NSM-CFRP Bars on the Shear Strength of RC Beams with Varying Depths and Concrete Strengths

To assess experimentally the effect of flexural near surface mounted (NSM) carbon fiber-reinforced polymer (CFRP) bars mounted on the sides of beams on the shear strength of reinforced concrete (RC) beams, 18 shear-deficient RC beams were built, strengthened with flexural NSM-CFRP bars, and tested under three-point bending until failure. The variables of the experimental program included the beam depth, the concrete compressive strength, and the flexural fiber-reinforced polymer (FRP) reinforcement ratio. It was observed that the strengthened beams exhibited up to 35% increase in shear capacity over the control beams. It was also observed that the increase in shear strength provided by concrete after strengthening was higher for beams with normal strength concrete when compared to those with higher strength concrete. The results have also revealed that the percent change in shear strength provided by concrete for the strengthened beams decreased with the increase in beam depth. Experimental data from this study showed that current standards become unconservative for beams with large depths. Five different beam shear strength models found in the literature were utilized to predict the shear strength of the tested beams. The models that exhibited the closest agreement with the experimental data were those of the University of Houston and the second order simplified modified compression field theory. It was concluded that flexural longitudinal NSM bars are a viable solution to enhance the shear strength of RC beams and that the shear strength provided by concrete can be accurately quantified using published models.

A Proposed Formula for Predicting Size Effect on Shear Strength of Concrete Beams Without Coarse Aggregate

In this research, the size effect on shear strength of concrete beams without coarse aggregate has been studied by evaluating the ACI 318-14, ACI 318-19, and Eurocode 2 formulas. The beam specimens had the width, length, a/d, and maximum aggregate size of 6 cm, 110 cm, 2.744, and 0.6 mm, respectively. The beam's depths had been set to have a range from 6 to 18 cm. The compressive strengths of the beam were in between 58.51 and 99.80 MPa. The beams had been tested under two concentrated loads. The longitudinal reinforcement consisted of two diameter 16 mm. The beams were designed without any stirrups. Based on the analysis, the ACI 318-19 approach provides the best prediction with the mean strength ratio and coefficient of variation of 1.5086 and 0.26, respectively. The ACI 318-19 also indicates insignificant downward trend on the strength ratio vs. effective depth. The test results show that the size effect is in good agreement with the Bažant’s size effect law. In this paper, modifications to the existing formula are given to provide more accurate prediction.

Shear capacity and behavior of high-strength concrete beams with openings

Transverse openings alter the structural behavior and undermine the integrity of concrete beams, resulting in stiffness degradation, shear strength reduction, stress concentration, premature cracking, and force-flow disturbances. Consequently, they require special attention during the design and construction of concrete beams with openings. Owing to the abrupt change in the beam's cross-sectional area, the strain distribution in the region around an opening is disturbed and nonlinear, making conventional bending and shear theories irrelevant. Few studies have investigated the impact of openings on concrete beams, especially that of openings on high-strength concrete (HSC) beams. Therefore, in this study, we perform tests on 12 reinforced concrete beam specimens to investigate the influence of depth, length, and location of openings on the ultimate shear strength of HSC beams with openings. The results revealed that the opening depth and length of HSC beams are negatively and almost linearly correlated to the ultimate shear strength; furthermore, based on their size and location, the shear capacity reduces by 2–53%. Similarly, the opening location along the shear span had a substantial impact on the capacity and behavior of the beam. Subsequently, finite element models of the tested beams were developed in ABAQUS software package and validated in compliance with the experimental results. The simulations exhibited good performance in predicting the ultimate strength, load–deflection relationship, and crack propagation in the beams. Accordingly, the developed models can be utilized to conduct further parametric studies and develop strut-and-tie models.

Carbon fiber/epoxy composite property enhancement through incorporation of carbon nanotubes at the fiber-matrix interphase – Part II: Mechanical and electrical properties of carbon nanotube coated carbon fiber composites

A new method to achieve a uniform coating of carbon nanotubes (CNTs) onto carbon fibers (CFs) has been developed which enables the scalable fabrication of CNT modified CF/epoxy composites. In this method, CNTs are coated onto CFs by immersion into a CNT/water suspension resulting in a uniform coating of CNTs. Unidirectional CF/epoxy composites with the CNT layer of 100–200 nm were fabricated by a prepregging method and mechanical/electrical properties were evaluated. The results show that the compressive, short beam shear strengths and Mode I interlaminar fracture toughness were improved by 22 %, 11 % and 48 % respectively after the incorporation of only 0.39 wt% CNTs. Electrical conductivities in 90˚ and through thickness direction were improved by two or three orders of magnitude (Log Resistivity: 1.24 and 2.31) respectively. These results indicate the importance of designing the fiber–matrix interphase to improve fiber reinforced polymer composite mechanical and electrical properties.

Shear Strength of Nano Silica High-Strength Reinforced Concrete Beams.

In this study, the shear strength of sixteen full-scale over-reinforced concrete beams with and without nano silica (NS), constructed from high-strength concrete (HSC), was investigated both experimentally and analytically. Nano silica was used as a partial replacement for Portland cement. According to the NS ratio, the tested beams were divided into four groups: 0%, 1%, 2%, and 3%. Shear span to effective depth (a/d) ratios of 1.5 and 2.5 were used in each group, and two different stirrups ratios (ρv) were employed as 0% and 0.38%. The shear strength provisions used by some international codes, such as the American Concrete Institute (ACI-2019), the Eurocode 2 (EC-2), and the Egyptian Code (ECP 207), were examined when applied to HSC beams with and without NS. The most important factors to consider were the effect of using NS on the shear span to effective depth (a/d) ratio and the shear strength of the beams with and without stirrups. The experimental results were validated using a nonlinear finite element analysis using the computer program ABAQUS. The experimental results showed that increasing the NS ratio reduced the number of cracks, and increased the cracks spacing, as well as reducing crack width. In specimens without stirrups, these effects were more obvious. A rise in the (a/d) ratio increased the number of cracks along the beam length, notably in the mid-span region. For specimens without stirrups and with an (a/d) of 1.5, raising NS from 0% to 1%, 2%, and 3% increased the ultimate load by 13%, 30%, and 39%, respectively, whereas for specimens with an (a/d) of 2.5, the ultimate load increased with approximately the same increase as that in beams with an (a/d) of 1.5 due to using NS. Additionally, the addition of NS to concrete boosted the contribution of the concrete to the shear strength, as shown by the results of beams without stirrups. For specimens with stirrups and an (a/d) of 1.5, raising NS from 0% to 1%, 2%, and 3% increased the ultimate load by 8%, 21%, and 30%, respectively. Additionally, for specimens with stirrups and an (a/d) of 2.5, the ultimate load increased with approximately the same increase as that in beams with stirrups and an (a/d) of 1.5 due to using NS. The test findings indicate that the shear strength calculated using the equations of the ACI 318-19 is more conservative than EC-2 and ECP 207 for NS concrete beams. The finite element program ABAQUS may be successfully used to predict the shear strength of NS concrete beams.

Improved Shear Strength Prediction Model of Steel Fiber Reinforced Concrete Beams by Adopting Gene Expression Programming.

In this study, an artificial intelligence tool called gene expression programming (GEP) has been successfully applied to develop an empirical model that can predict the shear strength of steel fiber reinforced concrete beams. The proposed genetic model incorporates all the influencing parameters such as the geometric properties of the beam, the concrete compressive strength, the shear span-to-depth ratio, and the mechanical and material properties of steel fiber. Existing empirical models ignore the tensile strength of steel fibers, which exercise a strong influence on the crack propagation of concrete matrix, thereby affecting the beam shear strength. To overcome this limitation, an improved and robust empirical model is proposed herein that incorporates the fiber tensile strength along with the other influencing factors. For this purpose, an extensive experimental database subjected to four-point loading is constructed comprising results of 488 tests drawn from the literature. The data are divided based on different shapes (hooked or straight fiber) and the tensile strength of steel fiber. The empirical model is developed using this experimental database and statistically compared with previously established empirical equations. This comparison indicates that the proposed model shows significant improvement in predicting the shear strength of steel fiber reinforced concrete beams, thus substantiating the important role of fiber tensile strength.