Influence of Concrete and Fiber Characteristics on Behavior of Steel Fiber Reinforced Concrete under Direct Shear

Khaloo, Alireza; Kim, Nakseok

doi:10.14359/344

Cited by 25 publications

(7 citation statements)

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“…The fiber factor F [125][126][127][128] takes into account the geometry of the fibers (length and diameter) [53,129], the amount of fibers (fiber volume fraction) [69,70,130], and the bond properties of the fibers, which depends on the fiber type [4,[131][132][133]. A challenge here was to ascribe bond properties to the less common fiber types that were encountered in the literature.…”

Section: Discussionmentioning

confidence: 99%

ANN-Based Shear Capacity of Steel Fiber-Reinforced Concrete Beams without Stirrups

Abambres

Lantsoght

2019

Fibers

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Comparing experimental results of the shear capacity of steel fiber-reinforced concrete (SFRC) beams without stirrups to the capacity predicted using current design equations and other available formulations shows that predicting the shear capacity of SFRC beams without mild steel shear reinforcement is still difficult. The reason for this difficulty is the complex mechanics of the problem, where the steel fibers affect the different shear-carrying mechanisms. Since this problem is still not fully understood, we propose the use of artificial intelligence (AI) to derive an expression based on the available experimental data. We used a database of 430 datapoints obtained from the literature. The outcome is an artificial neural network-based expression to predict the shear capacity of SFRC beams without shear reinforcement. For this purpose, many thousands of artificial neural network (ANN) models were generated, based on 475 distinct combinations of 15 typical ANN features. The proposed “optimal” model results in maximum and mean relative errors of 0.0% for the 430 datapoints. The proposed model results in a better prediction (mean Vtest/VANN = 1.00 with a coefficient of variation 1 × 10−15) as compared to the existing code expressions and other available empirical expressions, with the model by Kwak et al. giving a mean value of Vtest/Vpred = 1.01 and a coefficient of variation of 27%. Until mechanics-based models are available for predicting the shear capacity of SFRC beams without shear reinforcement, the proposed model thus offers an attractive solution for estimating the shear capacity of SFRC beams without shear reinforcement. With this approach, designers who may be reluctant to use SFRC because of the large uncertainties and poor predictions of experiments, may feel more confident using the material for structural design.

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Section: Discussionmentioning

confidence: 99%

ANN-Based Shear Capacity of Steel Fiber-Reinforced Concrete Beams without Stirrups

Abambres

Lantsoght

2019

Fibers

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“…The influencing factors chosen for modeling the shear behavior of steel fiber reinforced concrete (SFRC) beams herein are the concrete compressive strength, the tensile reinforcement ratio, the span to depth ratio, the fiber aspect ratio, the number of fibers in concrete, the fiber tensile strength, and the span of a beam. Of special interest in these parameters is the fiber tensile strength, which has been overlooked by all the previous studies [ 3 , 26 , 27 , 28 , 29 ].…”

Section: Factors Affecting Shear Strengthmentioning

confidence: 99%

“…Khuntia et al [ 27 ] have shown that the increase in the concrete compressive strength results in an exponential increase in the shear strength of steel fiber reinforced concrete (SFRC) beams, which has been attributed to the development of the strong bond between the concrete matrix and fibers [ 28 ]. Nevertheless, owing to the arching action, an exponential decrease in the beam shear strength is observed with an increase in the shear span-depth ratio [ 3 ].…”

Section: Factors Affecting Shear Strengthmentioning

confidence: 99%

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

et al. 2022

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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.

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“…The brittleness of reinforced concrete parts' shear failure is widely recognized. Steel fibers increase tensile behavior, ductility, and crack control in concrete [4]. Steel fibers also increase the shear load capacity and ductility of structural parts [5].…”

Section: Introductionmentioning

confidence: 97%

Shear Transfer Behavior of Fibrous Concrete

Jwad

Waryosh

2023

jeasd

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Fibrous concrete's shear strength behavior is important in structural design. Brackets, corbels, and ledger beams are examples of concrete members that might collapse in shear. Such a failure might be brittle and sudden. Fibers improve concrete's behavior by increasing residual shear transfer and reducing crack development and extension. In an experimental study, nine push-off specimens were divided into three groups and examined as part of the experiment. Conventional concrete, conventional concrete with 1% glass fiber, and conventional concrete with 1% steel fiber were the groups. There were three push-off specimens with various shear reinforcement ratios in each of the groups that were examined (0.0, 0.45, and 0.68%). The specimens utilized had dimensions of 500mm x 250mm x 125mm. The vertical slip and horizontal separation at the shear plane were measured using two-stroke linear variable displacement transducers (LVDT). The effect of fiber type and the ratio of transverse reinforcement across the shear plane were the parameters evaluated. The presence of fibers enhances final shear strength, which is more obvious in specimens without stirrups in the shear plane. Where the addition of 1% of glass fiber to normal strength concrete increased ultimate shear strength by 32.26%, 12.38%, and 12.5%, while adding 1% of steel fiber to normal strength concrete increased ultimate shear strength by up to 53.22%, 19%, and 25%, respectively, for the specimens without stirrups, two stirrups, and three stirrups. The fibrous specimens were stiffer and ductile failure was seen. Steel fibers improved overall concrete shear behavior better than glass fibers.

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Influence of Concrete and Fiber Characteristics on Behavior of Steel Fiber Reinforced Concrete under Direct Shear

Cited by 25 publications

References 0 publications

ANN-Based Shear Capacity of Steel Fiber-Reinforced Concrete Beams without Stirrups

ANN-Based Shear Capacity of Steel Fiber-Reinforced Concrete Beams without Stirrups

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

Shear Transfer Behavior of Fibrous Concrete

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