Design and construction of a composite arch bridge in Iceland

摘要

A 144 m long steel-concrete composite bridge over Fnjoska River in the northern part of Iceland has been built using closed box girders supporting prefabricated plate elements under cast in-situ concrete for the superstructure as well as for the arch. The 92 m long arch, a height/span ratio of 1:8, with its foundations on solid rock spans the river channel, which occasionally builds up a 9 m thick ice jam at the bridge site. Alternative solutions for the road layout were considered. A concrete arch bridge with post-tensioned superstructure was designed for bidding. In the design stage a careful study of the construction method was made considering the stability of the steel arches at the erection stage. This paper describes the principal design considerations for this structure with reference to the site's natural environment, aesthetics, traffic and seismic loads and construction method.