Prediction Model for Development Length of Corroded Prestressing Strand Considering Rotation-affected Bond Failure Mechanism

Evaluation of corrosion’s effect on the development length of prestressing strand is crucial for pretensioned prestressed concrete structures serving in the aggressive environment. This paper presents an analytical model for predicting the development length of corroded prestressing strand, in which the effects of strand corrosion on the transfer length and flexural bond length are considered separately. The effect of corrosion on the initial prestressing transfer length is analyzed by considering the combined effects of initial releasing cracking and subsequent corrosion-induced cracking on the evolution of confinement around the prestressing strand. Thereafter, beyond the transfer stage, the effect of strand corrosion on the additional flexural bond length is confirmed based on the calculation of maximum bond strength for various corrosion degrees, in which the effect of strand rotation along its axis is considered for the pull-out failure mode in a well-confined condition. Comparison of analytical and experimental results shows that this model can reasonably predict the development length of corroded prestressing strand.