Plastics may become the construction material of the future for lightweight, maintenance-free bridges. In Nørre Aaby, Denmark, a badly corroded concrete bridge has been replaced by a new type bridge made of GRP composite, popularly known as fibreglass.

The local authorities in Nørre Aaby have taken a new direction with the installation of a 23-metre long combined pedestrian and cycle bridge made of GRP composite. At first sight the new bridge appears unremarkable. In fact, it is a technologically advanced structure which is resistant to both weather and road salt and can also be installed in just a couple of hours, thus avoiding disruption to traffic.

According to municipal engineer Lotte Mogensen, the old bridge was in such poor condition as to be beyond economic repair. “The most economic solution was to install a new bridge made of GRP composite because it saved us having to close off the area for months,” says Lotte Mogensen, who is also delighted that the bridge fits in well with the local environment.

Re-using the existing foundations

The project engineer, Peder Fjordhauge of Vestfyns Arkitekt & Ingeniør, says that being able to crane the bridge into position in just a few hours, thus avoiding months of disruption to road users and residents alike, offers massive benefits.

“The GRP bridge weighs in at just six tonnes, compared with as much as 120 tonnes for a new concrete bridge. This meant that we could also save on new foundation works by re-using the existing foundations,” says Peder Fjordhauge.

The profiles for the new GRP bridge were made by specialist high-tech manufacturer Fiberline Composites. Subsequent assembly was performed by one of the company’s Dutch bridge building partners, after which the finished bridge was loaded onto a lorry and driven to its destination at Nørre Aaby. In the years ahead Fiberline Composites expects bridges built of its GRP profiles to become increasingly popular throughout Europe where many life-expired road and railway bridges are in need of replacement.