Study On Shear Capacity Of Steel Fiber Reinforced Concrete Beams Without Web Reinforcement

Steel fiber reinforced concrete(SFRC)can significantly improve the tensile strength,flexural strength,shear strength,ductility and other properties of concrete members.Therefore,steel fiber reinforced concrete(SFRC)is more and more widely used in practical engineering.At present,there is no unified formula for calculating the shear capacity of the oblique section of SFRC beams without web reinforcement.Therefore,through summary and analysis,the shear capacity of SFRC beams without web reinforcement is discussed and studied in this paper.The specific research contents and conclusions are listed as follows:1.The ultimate equilibrium theory and beam-arch effect are used to analyze the shear mechanism of SFRC beams without web reinforcement and their failure modes.Based on the splitting failure theory,the shear strength of SFRC beams is calculated and analyzed.This paper summarizes the existing calculation models of oblique section bearing capacity of SFRC beams without web reinforcement,and compares and analyses the characteristics and application scope of the formulas.Based on the assumption that the contribution of steel fibers to the inclined section bearing capacity of beams without web reinforcement is the enhancement of the tensile strength of SFRC,a calculation model of the bearing capacity of beams without web reinforcement is proposed.2.Based on statistical analysis of more than 600 groups of experimental data of shear capacity of oblique section of SFRC beams without web reinforcement,the relationship between average shear stress and tensile strength of oblique section of SFRC beams without web reinforcement,the relationship between shear capacity of oblique section and reinforcement ratio of longitudinal reinforcement,shear span ratio,characteristic value of steel fiber and its size effect are studied.The results show that the average shear stress of the oblique section of SFRC beams without web reinforcement is proportional to the tensile strength,and the influence coefficient decreases with the increase of shear span ratio;the shear capacity of oblique section is inversely proportional to the shear span ratio and positively related to the reinforcement ratio of longitudinal bars;the addition of steel fibers can weaken the size effect of SFRC beams without web reinforcement;3.By fitting the experimental data of shear capacity of oblique section of SFRC beams without web reinforcement,the influence factors of various factors in the calculation process of bearing capacity are determined,and a complete fonnula for calculating the bearing capacity of oblique section of SFRC beams without web reinforcement is obtained.The shear test results of SFRC beams without web reinforcement and statistical data validation analysis show that the application scope of this calculation model is verified and determined.