The mechanical behavior of Warrington-Seale (WS) strands as well as of a Warrington Seale rope with a polymeric fiber core is investigated. Specifically, the elasto-plastic response under axial loading conditions beyond the elastic limit is studied. Tensile tests were carried out on both WS strands and ropes. The strain–stress curves of single wires with different diameters were determined and used as input of a fully parametric Finite Element (FE) study aimed at investigating the stress and strain evolution in the rope in the elastic as well as in the elasto-platic regime. The numerical simulations, validated on the basis of the experimental results, are useful to shed light on the way the load is distributed among the wires. The different damage evolution and the most likely failure mechanisms of strands and of ropes were identified. Helpful remarks are drawn about the structural response of these components under heavy loading conditions.