A simplified contact-friction methodology for modeling wire breaks in parallel wire strands

Abstract

A simplified semi-analytical contact-friction approach is proposed to study the load transfer between tightened parallel steel wires, commonly used in suspension bridge main cables. Some of these wires tend to break at sporadic locations due to corrosion and/or material defects. However, owing to friction, in the vicinity of the break the load is distributed among neighboring wires and at a further distance away from the break, the broken wires recover partially their load carrying capacity.To model the load transfer due to friction, elasto-perfectly plastic springs are placed at the contact points between the wires. These springs have varying yielding force values, depending on their proximity to the clamping loads which are determined from an analytical solution to a point load (Flamant’s solution in 2D and Boussinesq’s solution in 3D). The model is validated on 2D and 3D simpler problems by comparing the behavior to a reference solution obtained from a full contact analysis.Studies on various sized wire strands, breaking at a random wire sequence and at different locations, show the redistribution of the stresses between neighboring wires and the overall nonlinear load-loss response of the system. Furthermore, to overcome the storage and speed limitations of serial computers, the method is implemented on a parallel computer architecture and the number of linear/nonlinear iterations, CPU time and parallel scalability are reported.