A partially transparent pedestrian bridge in fiber-reinforced composites is being built in southern Norway’s Fredrikstad.
“The bridge will be a landmark for Fredrikstad,” says Alf Egil Jensen, who is responsible for the composite sections that are being built using composites produced by Reichhold. “In order to comply with all requirements, the pedestrian bridge can only be built in this manner,” says Mr Jensen from the high-tech company FiReCo AS in Fredrikstad. His company is working closely with the engineers Inglistad & Tørnquist, the architects Griff Kommunikasjon, Borg Technology and engineer Evensen, to erect a drawbridge with a span of 60 meters over Vesterelva, a tributary to the Glomma River. FiReCo has specialized in composites and is responsible for the calculations regarding use of these materials.
The 60-meter long span consists of two sections, each measuring 30 meters. The point of landing is defined such that the bridge has a 1 in 12 gradient to allow the passage of boats underneath. “Very stringent requirements have been made with regard to dynamics. The only materials available that can provide the rigidity and weight required to satisfy all such requirements at the same time are composites. Given the shape of the bridge, it couldn’t have been built using any other sort of material,” says Mr. Jensen, who is not aware of any other instance in Europe where composites have been used in similar projects. In a Norwegian perspective, this project represents something completely new, but the material has been used to some extent in the United States, albeit very infrequently in projects of this size.
The company Marine Composites in Arendal is responsible for production of the various sections of the bridge. “The bridge sections are built like a boat. First we make a 27metre long mold, and then we mold the base using an injection process,” says Jon Inge Brattekås, managing director of Marine Composites. Subsequently, the bulkheads are prefabricated and struts are laminated into the base construction. “The deck is moulded in a separate mold, and the hull section and struts are laminated onto the deck. Finally, the transparent sides, in which Reichhold has played a role in developing the materials, will be assembled,” says Mr. Brattekås, who is very pleased with the use of Reichhold’s DION 9500 rubber-modified vinyl ester resin. Production time for the composites section of the bridge is approximately four months. The completed 12-ton sections will be transported from Arendal to Fredrikstad by barge. The sections will then be lifted directly from the barge onto the bridgeheads.
When the bridge is completed in the spring of 2003, it will be a distinguishing landmark.
Article reproduced, with permission, from the new issue of Reichhold’s composites customer magazine, Global Composites. The full magazine is available free of charge from Reichhold.
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