Monitoring and Assessment of 100 year Old Alzbrücke Seebruck

Alzbrücke Seebruck has been erected in 1933. It is a RC bridge using gerber hinges. These gerber hinges had been deteriorated over time in a significant way and the bridge was foreseen for replacement by a new structure. During preparation of the new structure the bridge should be kept open to the traffic for some 3 years. A monitoring concept has been established that allowed to check and assess the structural capacity in real time including check of traffic loads, alarm functions and all that based on static analysis. This paper shows the structure, the static details of the hinges, the monitoring concept and its results over time and lessons learned.