USE OF SHM IN DESTRUCTIVE TESTING OF BRIDGES

This paper present a fall-scale test on a strengthen railway concrete trough bridge. A unique opportunity came up. The existing railway line was going to be replaced with a new one and the bridge became obsolete. The purpose of the project was o investigate the shear capacity of the bridge. To avoid an uninteresting bending failure, the bottom beam were strengthened with Near Surface Mounted Reinforcement (NSMR) consisting of Carbon Fibre Reinforced Polymers (CFRP). The project was a part of the European funded research project Sustainable Bridges (www.sustainblebridges.net). The bride tested is a 50 year old two-span concrete bridge located in Ornskoldsvik in northern Sweden. The bridge was tested to failure to demonstrate and test new and refined methods developed in the project regarding procedures for condition assessment and inspection, load carrying capacity, measurement and strengthening. The bridge was built in 1955.It: has two spans of 12 m. In one of the spans a loading beam made of steel was placed in the centre of the span. The loading beam was then pulled down with cables injected to the bedrock beneath the bridge. Usually models for the load carrying capacity are tested in the laboratory in reduced scale. There are very few other concrete bridges which have been tested to failure in order to check their ultimate behaviour and this project demonstrate the use of SHM in full scale testing. The strengthening was successful and the results from the tests shows that the used design and FE-models underestimate the shear capacity considerably.