ABSTRACT
ABSTRACT: Monitoring is used to determine real structural response of post-tensioned concrete bridges under thermal and traffic loading. This is to assess the resistance of the prestressing steel at coupling joints of bridges erected in the 1960s and 1970s with span-by-span method. Heating of the bridge deck may lead to transition of the coupling section to cracked state II und subsequently to significantly higher stress range due to traffic. Hence, strain gauge based crack width sensors and temperature sensors are used for data collection. With the help of these real data the fatigue design of old bridges can be done more realistic (often less conservative) and avoid or limit the extent of strengthening measures. This article presents the monitoring concept and two exemplary projects: Köhlbrandbrücke in Hamburg (Germany) crossing the Elbe river and Neue Innbrücke in Schärding/Neuhaus (Austria/Germany) crossing the Inn river.
