| Summary: | The bond failure is studied of a reinforced concrete trough bridge strengthened with near surface mounted reinforcement of carbon fibre reinforced polymer (CFRP) bars. The bars were embedded in epoxy resin in pre-sawed groves in the soffit of the bridge edge beams. The failure was modelled with 3D nonlinear finite elements, and it was possible to study the process from initiation to final collapse. A local bond failure in the interface between the concrete and the epoxy resin initiated a redistribution of forces in the bridge leading to yielding in the longitudinal and vertical steel reinforcement, rupture of stirrups and finally a full failure of the bridge. The bridge was a 50-year-old typical concrete railway trough bridge in Örnsköldsvik, in northern Sweden. It was going to be dismantled due to a relocation of the railway line. The aim of the loading test was to get detailed information of the bridge behaviour all the way up to the final failure. The test was a part of the European Research Project “Sustainable Bridges” regarding assessment and strengthening of existing bridges. The bridge was strengthened in bending before the loading test to avoid an uninteresting flexural failure. Failure was reached for an applied load of 11,7 MN by pulling downwards a steel beam placed in the middle of one of the two spans. The FE calculations presented here show the effect of the strengthening with CFRP, the effect of the epoxy when using the Near Surface Mounted Reinforcement (NSMR) strengthening method and the high load-carrying capacity of this bridge type Forskningsfinansiär: European Union 6th Framewok Program; The Federal Institute for Materials Research and Testing (BAM); Botniabanan; Cervenka Consulting; Nordisk Spännarmering; Savonia University of Applied Sciences; University of Oulu; Skanska Sverige AB; STO Skandinavia AB; Örnsköldsviks kommun; University of Minho (UMINHO) Sustainable Bridges
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