Development Length of a High-Strength Steel Wire in a Bridge Cable Changing with Wrapping Force and Axial Load

This paper studies the force transfer of a large bridge cable containing a broken wire under wrapping force and axial load. Following our recent work, the wrapping force transferred through the contacts between the wires can be represented by a center-center force network with the Hertz contact, and the axial load is transferred to the broken wire by frictional shear along the contact in the axial direction. When a wire is broken, the stress is released at the free surfaces along the crack. However, the shear stress transfer from the neighboring wires to the broken wire concentrates through shear lag; therefore, the broken wire can regain load resistance over a certain development length, which can be estimated by stress analysis of the homogenized cylinder using the finite element method (FEM). The development length decreases when the wrapping force increases because the higher effective stiffness and interfacial shear resistance lead to a higher shear load transfer capacity. Consequently, given a specific wrapping force, the development length can be computed, allowing the prediction of the critical axial load of a cable with multiple broken wires with a certain spacing.