Stepwise Regression for shear capacity assessment of steel fiber reinforced concrete beams

Document Type: Regular Paper


1 Vali-e-Asr University of Rafsanjan, Rafsanajn, Iran

2 Department of Civil Engineering Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran


The addition of steel fibers into concrete improves the postcracking tensile strength of hardened concrete and hence significantly enhances the shear strength of reinforced concrete reinforced concrete beams. However, developing an accurate model for predicting the shear strength of steel fiber reinforced concrete (SFRC) beams is a challenging task as there are several parameters such as the concrete compressive strength, shear span to depth ratio, reinforcement ratio and fiber content that affect the ultimate shear resistance of fiber reinforced concrete (FRC) beams. This paper investigates the feasibility of stepwise regression (SR) to create an empirical model for the ultimate shear strength of SFRC beams without stirrups. The model produced by SR is constructed directly from a set of experimental results available in the literature. The results of training and testing sets of the model are compared with experimental results. All of the results show that SR model is fairly promising approach for the prediction of shear strength of SFRC beams. The performance of the SR model is also compared with different proposed formulas available in the literature. It was found that the SR model provides the most accurate results in calculating the shear strength of SFRC beams among existing shear strength formulas.


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