## 7 Proposed Prediction Equations  
Based on the test results summarized in Table 6, only the shear strength model proposed by [PERSON] in 2014 (Equation (11)), tends to be closer to the test results of series B2 compared to other proposed equations. The predicted results obtained by using Equation (11) are more precise and reasonable than the predicted results obtained by other researchers. However, based on examination of shear strength equations by using the shear strength database, Equation (11) is not as accurate as Equation (3). This is because the former exhibits the mean and COV of 1.43 and 0.58, respectively, while the latter shows the mean and COV of 1.27 and 0.35, respectively. The inability and inconsistency of previous equations in predicting the shear strength of SFRC beams prove that the need for a reliable equation to predict the shear strength of SFRC beams must be realized. Moreover, besides the agreement between the test and the predicted results, all previous prediction equations are still expressed as the summation of concrete contribution and steel fiber contribution. No study clearly presented the real mechanism of steel fibers in concrete nor expressed the steel-fiber and concrete beam parameters as one term. However, combining steel-fiber and RC beam parameters in one term can be assumed to be acceptable, since the steel fibers are also part of the materials in the SFRC beam, and it can only be expected that there must be an interaction between steel fibers and concrete. In this study, the prediction equation for SFRC beams is proposed by expressing the concrete and steel fiber parameters in one term. Also, the prediction equation is proposed such that in the absence of steel fibers, the equation is applicable to reinforced concrete beam without the steel fibers. Therefore, the prediction equation is expressed as the multiplication between the shear strength equation for normal RC beams and fiber effectiveness factor. The ACI 318-14 detailed equation for prediction shear strength [5] is adopted in this study, since this equation is a function of the tensile longitudinal reinforcement ratio, the shear span-to-effective depth ratio, and the square-root of concrete strength. In addition, the detailed shear strength equations provided in ACI 318-14 or older versions were developed based on the analysis reported in the ACI-ASCE Committee 326 report [5; 43], where the discussed failure modes were shear and diagonal tension. Therefore, developing the proposed equation for SFRC beams from an equation derived based on shear and diagonal tension is reasonable. The fiber effectiveness factor must contain the fiber aspect ratio, the fiber volume fraction, the bond strength along fiber-matrix interface, and the concrete strength. The relationship between ratios of shear stress of SFRC beam specimen-to-plain concrete beam (control specimen) and ratios of multiplication among the fiber aspect ratio, the fiber volume fraction, the bond strength along fiber-matrix interface to square-root of concrete strength are presented in Figure 8, in which the fiber effectiveness factor equation is derived through regression analysis. Based on test results summarized in Table 11, it is noteworthy that some authors only showed the shear strengths of SFRC beams without providing the shear strengths of plain concrete beams. Therefore, only 107 test results are involved in Figure 8a. Figure 8b shows the comparison between ratios of shear stress of SFRC beam specimen-to-plain concrete beam (control specimen) and predicted fiber effectiveness factors. The proposed equation is given in Equation (16), that was proposed such that only few data appear below the bottom dashed line in Figure 8b. This may lead the prediction equation to give a conservative result.