Full scale failure testing of a reinforced concrete bridge : photographic strain monitoring

Full-scale failure tests are rarely performed on structures, primarily due to their high costs and the lack of suitable test objects. The main aim of this test was to study shear failure of the bridge, which is a less understood and more difficult to predict mode of failure in RC structures than is bending. In order to prevent bending failure, it was necessary to strengthen the bridge using near surface mounted (NSM) reinforcements made of carbon fibre reinforced polymer (CFRP) bars. The bridge was heavily monitored during the test, using both traditional sensors such as electrical strain gauges and linear variable differential transducers (LVDTs) alongside new monitoring systems such as fibre optic sensors, strain rosette LVDTs, and a novel photographic monitoring system. This paper presents the results obtained from the photographic strain measurements and describes the use of the photographic tools in monitoring and characterising the behaviour of the failure zone during the full scale test. The strains measured using this method were found to agree well with those measured using classical strain gauges. In addition, the strain contour plots generated using the photographic method provided important insights into the strains within the bridge’s failure zone.Godkänd; 2012; 20120619 (gabsas