Shear Capacity of Reinforced Concrete Beams with Square Cross Section Subjected to Biaxial Bending

Abstract

This paper presents the test result of an experimental study on the shear strength of reinforced concrete beams subjected to biaxial loads. Six simply supported reinforced concrete beams with square cross section were used. Three beams rotated at 22.5 degrees and three beams rotated at 45 degrees to the applied load were tested until failure. All beams were subjected to four-point bending test. The test variable in this study was ratio of longitudinal reinforcement. The values of flexural crack load, diagonal crack load and the ultimate load were observed during the test as well as the midpoint deflection of the beams. Existing empirical equation for shear strength of concrete presented in design codes was used and then compared to the values obtained from the test. Comparison between test results and theoretical shear capacity show that all of equations conservatively estimated the occurrence of shear failure with the values of the test results 25 to 55% higher than the theoretical values depending on the ratio of longitudinal reinforcement. It was also observed that ratio of longitudinal reinforcement influences the angle of diagonal shear crack.