An analytical model for asymmetric wire breaking in unbonded prestressed single- and multi-strands

Abstract

A novel analytical model is proposed to improve the accuracy of predicting the mechanical response of a strand with asymmetrically broken wires. This model incorporates a new approach to compute the contact force between the broken wire and the duct. When there is more than one asymmetrically broken wire, the previous method cannot handle this situation due to the large deflection of the center wire near the breaking end. This deflection results in a significant contact force between the center and broken wires. The omission of this force in the previous method leads to unrealistic solutions for two or three asymmetrically broken wires. This paper addresses the issue appropriately. The calculated results have been compared with those from a previous experiment, demonstrating satisfactory agreement. Furthermore, the proposed analytical model has been adopted to predict the mechanical behavior of the broken wire in multi-strand scenarios relevant to a prestressed concrete bridge. The contact force between strands is accurately calculated. The findings indicate that the axial force of the asymmetrically broken wire in multi-strands can recover after a short distance from the broken end. This recovery is attributed to the confinement effect of the other strands.