Vibration reduction of suspenders of a bowstring bridge by means of cable bracing

Unanswered questions concerning the proof of fatigue resistance were the reason why in the years from 1999 to 2003 investigations were made in terms of measurements and calculations on the suspenders of a newly built bowstring bridge. Within the scope of continuous measurement, vortex excited vibrations relevant for fatigue appeared, which caused a need for action on different levels: on the one hand there was the need for vibration reduction of the relevant suspenders. For this reason minimised remedial maintenance work by means of cable bracing was developed, the planning and implementation of which is described in the following. On the other hand the findings gained were, at the time, in contradiction to the normative standards and regulations, and that caused a fundamental investigation concerning their revision and further development.