The bridge “Altstädter Bahnhof” in the city of Brandenburg a. d. Havel was a large pre-stressed concrete structure thatprovided an elementary traffic junction. In contrast to commonpre-stressed concrete structures with small tendons, large-format pre-stressing tendons were used in the longitudinal di-rection for the main superstructure. In the case of the presentbridge, the tendon consisted of 392 oval strands made in thesteel mill of Hennigsdorf, Germany, which are considered to besusceptible to stress induced corrosion cracking. During struc-tural investigations, a high degree of embrittlement of the pre-stressing steel was detected, so that the bridge had to be de-molished on May 19, 2021. Previously, in the area of detectedprestressing strand breaks, longitudinal cracks appeared in thewebs instead of the usual bending cracks. The different dam-age indication in the case of prestressing steel prompted theFederal Ministery of Transport to initiate further investigations.In cooperation with the Landesbetrieb Straßenwesen Branden-burg, the Hochschule für Technik und Wirtschaft Dresden andthe Bundesanstalt für Materialforschung und -prüfung (BAM),experimental investigations were designed and carried out onsite. Specifically, targeted damage to the large-format tendonwas carried out at two measuring points in order to reproduceand validate the damage pattern previously found. The con-cept, results from the investigations and findings for similarstructures are the subject of the following first article (Part 1).The following part 2 will focus on the measurement methodsand monitoring systems used during the experiments.