Wednesday, January 21, 2009

The previous post questioned WSDOT 's myoptic view that only a floating bridge could be used to cross Lake Washington. A google search turned up this gem of a response (keep in mind the deepest part of Lake Washington is 214'):

Why is WSDOT building a floating bridge over Lake Washington as opposed to a conventional suspension bridge? A conventional suspension bridge over Lake Washington would not work for several reasons:
Suspension bridges need to travel in a fairly straight line. Because SR 520 is a curved corridor, a suspension bridge would not be possible.
Lake Washington is between 200 and 400 feet, and the bridge’s support towers would have to be approximately 630 feet in height, nearly the height of the Space Needle, to support the bridge. These massive towers would be out of character with the surroundings because it would create more noise and block views.
Conventional fixed bridges, such as the new bridge over the Tacoma Narrows, are expensive to build in deeper waters with soft beds, such as Lake Washington.

1 comment:

Bernie Hayden said...

Gosh, "almost as high as the Space Needle". That was possible back in 1961 but all the old growth concrete has been cut down since then ;-)