Bond Strength of Reinforcing Bars Using Bearing Angle Model

Abstract

Despite the existence of many studies on bond strength of reinforcing bars in concrete, a theory-based analysis procedure applicable to design code is unavailable. For this study, analytical expressions with explicit formulae for the bond strength are proposed and compared with empirical equations. The proposed bearing angle model (BAM) incorporates the key bond force mechanisms and prime factors influencing bond strength. This paper presents the results of using the BAM for parametric analysis to explore the roles of the prime and design parameters on the bond strength. The analytical method was applied to the ACI 408 database and compared with descriptive equations. Herein, the dataset consisted of unconfined, confined by transverse reinforcement, top-cast, or epoxy-coated bars and those with high relative rib areas. The suitability of the proposed method with the analytical expressions was evaluated through comparison with existing data; the evaluation indicated reasonably accurate estimation of the experimental results for test specimens.