Nordhordland BridgeEdit profile
Nordhordland Bridge is a bridge that crosses Salhusfjorden between the mainland and Flatøy in Hordaland county, Norway. The bridge connects the district of Nordhordland to the city of Bergen. Nordhordland Bridge is a pontoon and cable-stayed bridge with one tower. it is also the second tallest bridge of Norway. The bridge is 1614 metres long (not 1610, as it is sometimes inaccurately stated). The cable-stay part of the bridge has 19 spans. Due to the 500 metre depth of the sea beneath the bridge, lateral anchorage between the abutments at each end was not possible. To accommodate this unusual condition, there was a great deal of additional analysis in design of the footings at each end of the bridge. The free-floating bridge has the longest laterally-unsupported span in the world. Nordhordland Bridge was opened in 1994 as the second permanent pontoon bridge in Norway.The bridge ceased being a toll bridge on December 31, 2005 at 16:00. In 2007, the bridge had an average daily traffic of 13,239 vehicles, up from 7975 vehicles in 2000. Contents
Construction Floating bridge ( pontoon bridge) construction has a long history in military and civilian applications on every continent except Antarctica. According to the engineers who designed this bridge, it was designed using recent American technology for floating bridges, combined with Norwegian technology for offshore platforms. The Norweigan bridge designers researched other bridges in the world and traveled to Washington State, USA to visit the Homer M. Hadley Memorial Bridge and the Hood Canal Bridge, two floating bridges. The continuous floating concrete structure used in the Washington bridges was ultimately ruled out in favor of the an orthotropic deck of steel as the superstructure on top of floating concrete pontoon. The first Bergsøysund Bridge design used steel trusses made of steel pipes with orthotropic deck of steel. These steel trusses are supported by concrete pontoons. The 2nd designed uses a large octagonal tube or steel box girder bridge made of orthotropic deck of steel on all eight sides for the floating portion. The box girder bridge system is the most materially efficient to handle torsional forces. The Washington designs have steel truss bridge spans at the ends of the floating bridge, so sailing vessels can pass through. The Nordhordland Bridge has a cable-stayed bridge span at one end of the floating bridge, so sailing vessels can pass through. The posted photo shows a ramp connecting the higher cable-stayed bridge span to lower pontoon bridge. This design afforded: 1) an elevated roadway that reduced traffic hazards in storms, 2) a reduction in corrosion of the bridge deck, and 3) improved passage of water beneath the bridge thereby supporting native species.