Strengthening of a Concrete Bridge and Loading to Failure

A single span bridge built in 1912 was replaced and subjected to tests. One of the two girders was used to check the shear verification concept of those days. The other girder was strengthened with CFRP (carbon-fibre-reinforced plastic) laminates to increase flexural resistance. Load tests up to failure displayed a sufficient shear resistance and a ductile behavior in bending in spite of the old concrete of low quality. After the laminates had peeled off, the girder was further loaded in order to investigate the response after delamination. The test showed that strengthening with CFRP laminates can be a viable option even for very old concrete bridges and that peel-off failure can be prevented by consideration of the interface shear stresses.