Shear-stress transfer across a crack in steel fibre-reinforced concrete

Soetens, Tim; Matthys, Stijn

doi:10.1016/j.cemconcomp.2017.05.010

Cited by 65 publications

(25 citation statements)

References 13 publications

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“…the shear strength strongly depends on the longitudinal reinforcement ratio [139], as a result of the larger contribution of dowel action [64,120,123,124,140,141] for larger amounts of reinforcement, 2.…”

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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“…Shear strength increases by 44% for the steel fiber volume fraction of 0.5% and 65% for the volume ratio of 1% [17]. e shear strength of SFRC exhibits a linear increase with the amount of steel fiber crossing the shear crack interface [18]. It can be seen that even if the content of steel fiber is the same, steel fiber still has different reinforced effect on different mechanical property.…”

Section: Introductionmentioning

confidence: 91%

Effect of Surface Shape and Content of Steel Fiber on Mechanical Properties of Concrete

Zhang

Zhao

Fan

et al. 2020

Advances in Civil Engineering

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Steel fiber reinforced concrete (SFRC) has gained popularity in the last decades attributed to the improvement of brittleness and low tensile strength of concrete. This study investigates the effect of three shapes of steel fibers (straight, hooked end, and corrugated) with four contents (0.5%, 1%, 1.5%, and 2%) on the mechanical properties (compression, splitting tension, shear, and flexure) of concrete. Thirteen groups of concrete were prepared and investigated experimentally. Test results indicated that steel fiber had significant reinforcement on mechanical properties of concrete. When the steel fiber content increases from 0.5% to 2.0%, the compressive strengths increase about 4–24%, splitting tensile strengths increase about 33–122%, shear strengths increase about 31–79%, and flexural strengths increase about 25–111%. Corrugated steel fiber has the best reinforced effect on strength of SFRC, hooked end steel fiber takes the second place, and straight steel fiber is the least. Calculated formulas of compressive, splitting tensile, shear, and flexural strengths were established with consideration of the bonding properties between concrete and steel fiber. Influence factors of steel fiber αf and concrete matrix strength αc were put forward and determined by regression analysis of experimental data. Calculated results agree well with the experimental results.

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“…The conclusions revealed that yield stress played an important role in fibre orientation and, hence, in shear strength) (see Figure 2-22b). As both compressive strength and fibre content increased (see Figure 2-22c), shear also improved, but the ductility due to fibres improved more in the normal and self-compacted concretes than in the high-strength concrete [134] In 2017, Soetens and Matthys [135] modified JSCE-SF6 to control the normal stresses in the crack, as seen in Figure 2-23a. Thus different horizontal load levels were applied and remained constant during the test.…”

Section: Figure 2-19mentioning

confidence: 99%

“…Evidently, both test methodologies presented different failure aspects because one shear plane existed in one case, the second one included two shear planes. In the FIP tests conducted by Khanlou et al, (see Figure 2-26b), the friction between the specimen and supports was isolated by using rollers, while the specimen was fixed to a support table to avoid undesired rotations in the test of Boulekbache et al In this way, undesired horizontal strengths can be introduced into the test by means of friction and not measured as Soetens and Matthys [135] did. To clarify this point, more information about test measurements, and a comparison among the tests proposed in the literature, are required.…”

Section: Fip Shear Testmentioning

confidence: 99%

“…It is possible to control crack opening by means of an active (bar reinforcement) or passive mechanism (external mechanism) that acts normally to the shear plane. Several authors have done this to study the crack kinematics under crack control conditions using an active or passive mechanism [82,92,127,135]. This confinement effect can be formulated by normal stress, which depends only on crack opening.…”

Section: Confinement Effect By An Active or Passive Mechanismmentioning

confidence: 99%

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Effectiveness of polypropylene fibres as shear reinforcement in structural elements

Navas¹,

Roberto²

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Several efforts have been made in experimental and theoretical research about shear to understand all the variables that influence the phenomenon. Nowadays, however, due to its complexity, the shear performance of structural concrete elements, especially those without any traditional transversal reinforcement, continue with no clear explanation of the problem. Uncertainty about the problem grows when new variables like fibres are incorporated into the shear study.Research works have demonstrated the effectiveness of steel fibre in improving the mechanical properties of concrete elements. Experimental results reveal that steel fibres have proven effective in improving shear resistance, and they confer some concrete elements more ductility. In adequate amounts, steel fibres can completely or partially substitute traditional shear reinforcements. This is why international codes have included some requirements to take into account the action of fibres on the shear response of concrete elements. However, most recommendations and requirements for steel fibre-reinforced concrete (SFRC) were originally created.New fibres with different materials properties and shapes, such as macrosynthetic fibres, are now available on the market. These fibres, some of which are made of polypropylene, are an alternative in the construction industry given their properties and final cost. Initially, polypropylene fibres were used to control shrinkage cracking. Nevertheless, in the last decade the chemical industry has created larger fibres with better surface shapes, which allows polypropylene fibres to meet the requirements of international codes so they can be used in structural elements.Per avaluar l'efectivitat de les fibres de polipropilè en el tallant, es realitzaran tres campanyes experimentals. Cada campanya representa un nivell d'estudi diferent. El primer és a nivell material on s'avalua el comportament a tallant a través d'espècimens tipus Push-off. El segon nivell, correspon a l'estudi del tallant en elements a escala real. Per això es fabriquen i assagen bigues esveltes crítiques a tallant. L'últim nivell correspon a una aplicació real de fibres de polipropilè actuant com a reforç a tallant. En aquesta campanya, es fabriquen i assagen plaques alveolars de gran cantell amb seccions i condicions de suports reals.

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Shear-stress transfer across a crack in steel fibre-reinforced concrete

Cited by 65 publications

References 13 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

Effect of Surface Shape and Content of Steel Fiber on Mechanical Properties of Concrete

Effectiveness of polypropylene fibres as shear reinforcement in structural elements

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