Analytical bond strength of deformed bars in concrete due to splitting failure

Abstract

The bond behavior of deformed bar in concrete is important for the design and analysis of concrete structures, especially with insufficient concrete cover or confinement. This paper presents an analytical solution for the bond strength of deformed bar in concrete due to the splitting failure of concrete cover. A hypothesis of the equivalent elastic deformation field is proposed to approximate the deformation within the inner cracked concrete, while a linear crack profile is assumed to formulate the width of fictitious cracks. In conjunction with a realistic softening relationship, the analytical solutions of the internal pressure and bond strength are then derived for the splitting failure. The comparisons between the analytical predictions and the extensive experimental results demonstrate that the presented analytical model is capable of predicting the bond capacity with good accuracy. Finally, the influences of geometric and material parameters on the prediction results are examined, and an expression for the required bonded or splice length is suggested for design applications.