Experimental and theoretical study on the bonding property between PC steel bar and concrete under monotonic and cyclic loading

Abstract

To study the bond performance of the plain round steel bar for prestressed concrete (PC steel bar) in concrete, the bond tests were carried out on specimens with different concrete strength grades (C30, C40, C50 and C60) and bonding lengths (40 mm, 80 mm and 12 mm) under monotonic and cyclic loading. The test results showed that the bond stress-slip curves of specimens with different concrete strength and bonding lengths were similar under monotonic and cyclic loading, and the shape of hysteresis curves was symmetrical about the origin. The peak bond stress and residual bond stress decreased with the increase of bonding length, which increased with the increase of concrete strength. The slip corresponding to peak bond stress increased with the increase of bonding length and concrete strength. According to the test results, the equations for calculating the bond stress-slip curve, the peak bond stress and its corresponding slip under monotonic loading were obtained, respectively. Then the bond stress-slip model was proposed by providing the skeleton curve, hysteresis paths and rules under cyclic loading. By comparing the calculated results of the model with the test data, it has been proven that the model can predict the bond stress-slip curve between PC steel bar and concrete with different concrete strengths and bond lengths.