Semi-empirical synergetic analysis of the shear capacity of steel fibre reinforced concrete slender beams of rectangular-sections without stirrups

Abstract

Although steel fibre reinforced concrete (SFRC) has been widely used in various engineering structures, there is a lack of a reliable and unified method for predicting the shear capacity of reinforced SFRC slender beams. After conducting an extensive review of previous studies on the slender beams of rectangular-section without stirrups and the SFRC with the cold-drawn hook-end steel fibre, a database was developed based on 280 reinforced SFRC slender beams that failed in shear accompanied by 37 reinforced SFRC slender beams failed in flexure and 71 reinforced conventional concrete beams failed in shear. The comparison between the experimental results and the results predicted using existing formulae revealed that a more accurate empirical model is required to evaluate the effects of multi-factors on the shear strength of the reinforced SFRC slender beams without stirrups. Based on the model of the critical shear crack, a semi-empirical synergetic equation is developed to predict the shear capacity of reinforced SFRC slender beams without stirrups. The enhanced shear resistance of SFRC in the shear-compression zone, the dowel action of longitudinal tensile steel bars, the aggregate interlock between sides of critical shear crack, and the shear resistance of steel fibres across the shear cracks as well as the size effect of sectional depth are considered. Good prediction results with small dispersion can be obtained using the proposed semi-empirical model. Conservative and simplified equations are also provided as the lower bound of the experimental shear strength of the reinforced SFRC slender beams without stirrups for easier implementation of the proposed model in real engineering design practice.