External prestressing is a construction technique widely used since the 1980s for large civil engineering structures to reduce the cross-sectional area of structures and thus their permanent load, and more recently to reinforce structures. External prestressing tendons are composed of strands, each comprising 7 wires with a very high elastic limit, laid in a HDPE sheath, anchored in reinforced concrete blocks and generally tensioned to 80% (excluding creep and shrinkage) of their ultimate tensile strength. To protect the cables, cement grout was injected into the sheaths until the 2000s. However, this protection system does not preserve the cables in the event of a sheath failure (leakage, injuries, etc.) which compromises its watertightness and causes issues with the quality of the injection. The durability of the cable is therefore no longer guaranteed and stress corrosion occurs. When the wires and strands re-anchor by friction in the grout after breaking due to corrosion, the stress of the remaining of the tendon increases until the breaking load of the whole tendon is reached. The break is then very sudden, releasing considerable energy that can endanger the structure and any operators present on site. Knowledge of the state of the cable at a given level of degradation and the permissible degradation before it breaks is therefore of prime importance to the managers of the structures. Several 46m long cables between supports were tested using the cable traction bench of the Gustave Eiffel University in Nantes and brought to failure by progressive cutting of the wires composing the strands. Firstly, three tendon comprising a single strand of seven wires were tested, followed by two tendon comprising five strands. The tendons were tensioned to 70% of their breaking load corresponding to the usual stress level observed in the tendons of real structures having subjected to shrinkage and creep phenomena. The experiments conducted and the analysis of the results have provided a better understanding of the evolution of the tension in the tendon when it is damaged. For this purpose, a model was developed which allows to obtain an estimate of the length affected by the rupture of wires (transfer length) and this work brings some results concerning the transfer of stresses in the tendon and strands caused by these ruptures.