Bond-slip behaviour of steel bars in low-strength concrete

This paper presents the bond-slip models for deformed and plain bar types in low-strength concrete. The newly developed bond-strength models were used to account for the effect of different deficient variables typically found in non-engineered reinforced-concrete structures in developing countries, such as low-strength concrete, insufficient development length and low concrete cover. Residual bond strength was evaluated from experimental bond-slip curves by defining approximate criteria for calculating residual slip. Suitable bond-slip relationships are identified to define local bond-slip relations for both bar types in low-strength concrete. Based on the experimental findings, the strain distribution profile over the development length is proposed, which can be used to evaluate the bar elastic slip in low-strength concrete by employing the macro model. The proposed bond-slip models can be used in the inelastic analysis of non-engineered reinforced concrete structures.