Evaluation of the durability of prestressed reinforcements in prestressed concrete superstructures
Old bridge superstructures exhibiting cracks across the prestressed reinforcement need detailed inspections for estimating maintenance requirements. Of special importance here is a clarification of whether or not the prestressed reinforcement poses a long-term stability problem.
Only this type of evaluation makes it possible to determine the required extent and nature of maintenance. To minimize costs, it is necessary to segregate non-critical cases and identify long-term stability problems, assigning them to different classes of severity.
In past years, a number of old structures built in the federal states before introduction of the supplementary technical contract conditions for man-made structures, 1980 edition and DIN 4227 part 1, 12/1979 edition and exhibiting, in particular, cracks in their coupling joints, have been overhauled. These structures were evaluated on the basis of different assumptions using a variety of techniques.
Meant to ensure use of a universal, standard procedure, this directive stipulates binding assumptions and limiting stress values.
Enacted with StB 25/38.55.10 -07/26 BASt 98 dated 25th June, 1998, the directive applies to the business segment of federal trunk roads.