CRITICAL CASE

摘要

Conditions at the Halogaland Bridge alignment - notably the 350m-deep water and 1.3km-wide crossing at Rombaksfjord -made a cable-supported bridge the only realistic solution for the design team which Statens Vegvesen commissioned in 2007. A single span suspension bridge was the most economical option, since there was good quality rock readily available for anchors, and was studied by a design team, led by Cowi with Dissing & Weitling, Johs Holt and the Norwegian Geotechnical Institute. During the project development phase, basic design and construction cost estimates were prepared for two solutions. The first had its towers founded on the land, on rock, and a 1,345m-long main span; it would have been the longest suspension bridge in Norway. The second alternative considered had a 1,120m-long main span and towers founded on caissons in the sea at water depths of approximately 25m. The latter solution enabled a saving of approximately US$17 million, mainly due to the fact that a connecting tunnel was reduced in length.