Stress corrosion cracking (SCC) is a brittle failure mechanism in prestressing steel that occurs without visible indications on the concrete surface and may lead to sudden structural collapse. Numerous existing bridge structures in Germany are at risk due to SCC-susceptible steel, particularly those constructed before 1990. The collapse of the Carola Bridge in Dresden in September 2024, which occurred without prior visible signs of damage, highlights the need for reliable monitoring methods for early detection of such failures. Manual visual inspections are inadequate, as SCC is not detectable under direct observation of the concrete surface. Distributed fiber optic sensors (DFOS) enable high-resolution, quasi-continuous strain measurements over extended structural lengths and can detect even small strain variations caused by the breakage of individual prestressing wires. To evaluate the potential of this approach, prestressing wires were cut on a post-tensioned concrete girder during a four-point bending test. The results show that even single wire breaks induce characteristic strain redistributions detectable by DFOS, providing the basis for a strut-and-tie model describing load redistribution.