Quantification of non-uniform mechanical interlock and rotation in modelling bond-slip between strand and concrete

Abstract

A quantification method of the non-uniform mechanical interlock and rotation is proposed for modelling the bond-slip behavior between steel strand and concrete. The bond stress incorporating the non-uniform mechanical interlock is derived based on the developed three-dimensional (3D) mechanical model. A theoretical model of strand slip including rotation is established using the energy conservation law. The proposed method is verified by comparing with the predicted and experimental results. The effects of the mechanical interlock and rotation on the bond-slip of strand are also discussed. Results show that the proposed method can reasonably model the bond-slip behavior between steel strand and concrete. For the typical seven-wire strand, the theoretical prediction accuracy of the bond stress and slip can be improved by considering the effects of the non-uniform mechanical interlock and rotation. The non-uniform mechanical interlock restrains the overestimated bond stress and the strand rotation contributes to the slip.