Bridge Surface Made of Plastic
At the end of July in Friedberg (Hessen), Europe’s first composite steel/glass-reinforced plastic bridge was completed. It crosses over Federal Highway 455 and is the result of several years of cooperation between the Hessian State Office of Transportation and Roads (HLSV) and the Institute for Supporting Structures and Construction Design (ITKE) at the University of Stuttgart.
The 27-meter-long and five-meter-wide bridge contains two steel girders. Attached to these are glass fiber-reinforced plastic profiles that have been bonded together to form a 22-cm-thick roadway. An approximately four-centimeter-thick layer of polymer concrete based on epoxy resin forms the actual road surface. The surface roughness and wear resistance of the novel road surface comply with all requirements for such applications.
The new design makes it possible to dispense completely with steel-reinforced concrete or asphalt. This translates into a considerable weight savings: the steel/glass-reinforced plastic bridge weighs in at merely 58 t, so that it can be transported on a low-bed trailer and lifted by mobile cranes. This means that the bridge can be installed in only a few hours and can then be opened to traffic immediately. The bridge itself is assembled off-site at the production facility.
Downstream costs also point to the benefits of this new type of bridge, since bridges made of steel-reinforced concrete with an asphalt surface often need extensive repairs after only 15 to 20 years. The costs associated with this work can amount to 50 % of the original cost of the bridge. Compared to a steel-reinforced concrete structure, the composite bridge is about 50% more expensive, but if – as projected – composite bridges can last up to 50 years without needing repairs, they represent a more economical solution in the long term.