Analytical derivation of rib bearing angle of reinforcing bar subject to axial loading
This paper documents a study carried out to formulate the rib bearing angle in initial bond stress-slip for deformed reinforcing bars under axial loading. An analytical approach is proposed that utilises the conventional Mohr-Coulomb material properties. A universal maximum rib stress bearing angle is formulated as the complementary angle of the internal friction angle of surrounding concrete. For a given bar, the rib bearing angle can be narrowed down further. An equation for the estimation of the most possible rib bearing angle is formulated as a function of the material properties and the confinement level. The analytical results presented in this paper indicate that the most likely rib bearing angle is around 25° for an unconfined reinforced concrete structure. The validity of the proposed theory is established by comparing the analytical results to the experimental data in the literature.