Analysis of bond splitting failure of deformed bars within structural concrete

Abstract

The strength limit state of embedded bars and lap splices in reinforced concrete is often governed by splitting of the surrounding concrete, due to radial pressure exerted by the bar lugs. In this paper, finite element models are used to study the influence of lateral reinforcement, concrete strength, and the positioning of the main reinforcing bars on the development of such bond splitting failure in reinforced concrete. Planar analyses are conducted for pullout and lap splice specimens tested in previous experimental programs. It is shown that the bond splitting strengths obtained from testing are nearly proportional to the maximum average radial stress values obtained numerically. The proportionality constant is not significantly influenced by the amount of transverse reinforcement or concrete strength. For greater amounts of transverse reinforcement, the compressive stresses transferred between the main reinforcing bars can be large to the extent that bond strength is governed by compressive failure of the concrete. Even for such cases, however, the effects of the residual tensile strength of the concrete in the splice region cannot be neglected.