Wednesday, February 25, 2009

Arch Bridges: The Rainbow Bridge

The Niagara is one of the few rivers in the Northern Hemisphere that flows northward.  Lake Erie is 326 ft (99 m) higher in elevation than Lake Ontario.  About half of this change in elevation occurs at Niagara Falls, 17 miles (27 km) from the river's mouth.

Downstream from the falls is the Rainbow Bridge, a 950 ft (290 m) long deck arch that was opened in 1941.  Two cross-braced steel box girder arch ribs support spandrel columns, floor beams, steel stringers, and a concrete deck.  The arches start 50 ft (15 m) above the water's surface to avoid the ice flows that destroyed the previous bridge at this site.  Nets were provided under the bridge during construction, which caught workers and prevented casualties. 
A history of all the bridges crossing the Niagara River can be obtained at: http://www/iaw.com/~falls/bridges.html
Creative Commons License
Arch Bridges: The Rainbow Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-Noncommercial 3.0 United States License.

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