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.