The Strengthening Of A Steel Bridge With Prestressed Cfrp Strips

The use of CFRP (carbon fibre reinforced polymer) strips in steel strengthening works has gone through a big development during the past 15 years. However, only in a few studies the effect of prestressing on the behaviour of steel beams strengthened with the CFRP strips has been examined. The paper briefly describes the research on the new CFRP strips prestressing system with special steel anchorages and its first on-site application for a steel bridge strengthening. The bridge proof tests before and after strengthening have been carried out. The results of testing proved the strengthening efficiency, however the final effect was moderate. As a result of strengthening the following effects has been gained: max. 18.3 % reduction of mid-span deflection and max. 13.9 % reduction of stresses in steel beams. The CFRP strengthening slightly improved the overall dynamic performance of the bridge span as well. The tests results showed moderate strengthening effects, mainly due to beams geometrical constraints not allowing to apply more than one 60 x 14 mm strip per beam. Regardless the moderate efficiency of strengthening, the research results clearly revealed that the new strengthening technology could be efficiently applied for steel bridges.