Sunday, October 16, 2011

Michigan's Bridges: Blue Water Bridges across the St. Clair River (2)

March 1990 (42.999 Degrees, -82.424 Degrees) Blue Water Bridge
Until 1997, there was only one Blue Water Bridge. It was a two lane river crossing, built in 1938 by Ralph Modjeski and the state of Michigan with a main span of 871 ft.

Bridge projects are interesting examples of the mutual needs of people that result in the agreements, in the money (through government bonds), in the technical resources, the skilled workers, and eventually in an iconic structural design.

The west approach and the river crossing were designed and build in the US while the eastern approach was build by the province of Ontario. This resulted in the second busiest US-Canadian crossing for goods and materials between the two countries. It's really not much different from the little suspension bridges that Walter Yanez builds in Ecuador to help bring prosperity to the poor farmers needing to bring their goods across the rivers in Ecuador.

The figure below is a nice illustration of how to build a cantilever truss bridge. Like a teeter-totter, each cantilever balances on short piers while they are anchored to huge and rather ugly four-legged back piers.
Courtesy of the State of Michigan
Creative Commons License
Michigan's Bridges: Blue Water Bridges across the St. Clair River (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

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