Strengthening of bridges with pretensioned FRP laminates: experimental investigation and a case study

A number of experimental investigations on fibre reinforced polymer (FRP) are available in the literature but very few information is available on specimens strengthened with pretensioned FRP laminates. An experimental study on real-scale RC and PRC beams strengthened in flexure with FRP laminates, devel- oped at the University of Padova, Italy, together with a related case study is described in this work. Externally bonded FRP reinforcement was applied in different ways with different types of end-anchorage devices and, in some beams, pre-stress transfer. After characterization of the single materials, four-point bending tests were executed and crack pattern and failure modes were studied. This FRP pretensioning tecnique was applied for strengthening the girders of the Battiferro – Navile viaduct (A14 Highway Bologna-Taranto, Italy). The bridge had about 40 years and showed structural problems due to concrete deterioration and significant increase of traffic weight. The intervention has regarded both main lon- gitudinal and transversal beams.