Modelling of bond between three-wire strands and concrete

The bond between strands and concrete is of importance for prestressed concrete. The research presented in the current paper aims at a better understanding of the bond mechanism, and of how different detailings of the strand interface affect the behaviour. A bond model for three-wire strands was established and calibrated by use of pull-through tests. The results from finite element (FE) analyses with the bond model and the tests were used in parallel. It was found that adhesion, friction and the ability to develop normal stresses determine the bond response of the strand; consequently, they were used as input parameters in the bond model. How different detailing of the strand surface affects these parameters, and the influence on the bond mechanism, are shown. For example, adhesion has the strongest influence on the initial bond response in the cases of smooth and indented strands. Regarding indented strands, the maximum bond capacity is determined by the strand indentation. The knowledge gained can be used to design the strands for a certain bond behaviour.