3D non-linear FE analysis of a full scale test to failure of a RC Railway Bridge strengthened with carbon fibre bars

Abstract

At a full scale loading test to failure a 50 year old concrete railway trough bridge in Örnsköldsvik, in northern Sweden was tested to failure. The test was a part of the European Research Project "Sustainable Bridges" regarding assessment and strengthening of existing bridges. In the project new calculation methods were developed to capture the behaviour of the bridge during increasing load. The bridge was strengthened in bending with rods of Carbon Fiber Reinforced Polymer (CFRP) before the loading test. Failure was reached for an applied load of 11.7 MN by pulling a steel beam placed in the middle of one of the two spans downwards. The achieved failure was a combination of bond, shear, torsion and bending. The developed model, a 3D -non-linear finite element (FE) model with discrete reinforcement, gave accurate accounts of the response of the bridge. The FE calculations show the effect of the strengthening with CFRP and even the effect of the epoxy when using the Near Surface Mounted Reinforcement (NSMR) strengthening method.

More Realistic Codes for Existing Bridges

“…[5] - [8], [14]. They agree well with the test results and the ones with 3D non-linear modelling of the bond behaviour are quite accurate [8].…”

“…Several finite element models have been made of the bridge with various complexity, see e.g. [5] - [8], [14]. They agree well with the test results and the ones with 3D non-linear modelling of the bond behaviour are quite accurate [8].…”

“…To obtain a shear failure, the bridge was strengthened before the final failure test with 18 (nine per beam) 10 m long near surface mounted (NSM) carbon fiber reinforced polymers (CFRP) bars, each with a 10×10 mm cross section. The modulus of elasticity and the tensile strain at failure were 250 GPa and 0,8 %, respectively [5]- [8].…”

“…The bridge consisted of two outer beams supporting a slab in two spans (12 + 12 m), with a slight longitudinal curvature (R = 300 m) and supports skewed with an angle of 17 degrees. It was taken out of service in 2005 when a new highspeed railway line, the Bothnia Line, was built[5]-[8]. The bridge was designed for a 40 MPa concrete and steel reinforcement with yield strength of 400 MPa.…”