Detektieren ermüdungsbedingter Spannstahlbrüche mittels Rissmonitoring im Versuch und am Bauwerk

摘要

On a prestressed concrete bridge in the region of the point of zero moment due to permanent load systematic crack formations with crack widths up to 0.5mm were detected. These cracks were a consequence of the restraint moments due to temperature (Delta T-M), which have not been considered at that time. As a result of the cracks, the tendons were endangered by fatigue. Even with more refined methods, it was not possible to verify sufficient fatigue resistance. In addition, the overall structural condition was in a poor state.Therefore, the road authority decided to build a new bridge as replacement as soon as possible. Up to that point the structural safety of the bridge had to be ensured. For this purpose, continuous crack monitoring was carried out for the critical areas. Fatigue tests on prestressed concrete components atTU Dortmund University formed the basis for its evaluation.These tests succeeded in reliably identifying individual wire breaks during the ongoing test and in developing a prognosis method for the remaining service life.The experiences and difficulties of transferring these methods to a real structure are reported.