Wednesday, July 7, 2021

1956 US-30 Gateway Suspension Bridge over Mississippi River at Clinton, IA

(Bridge Hunter; Historic Bridges; John A. Weeks III; Satellite)

The UP/C&NW Bridge is in the background.
John Weeks
"This bridge has a rather interesting design. Notice that the cables are straight on the ends of the bridge, but sag in a curve between the towers. The reason for the cables being straight outside of the towers is that there are no vertical cables hanging down to support the bridge. If you look at a typical suspension bridge, there are vertical cables, and that pulls down on the main cables, causing them to form curves. This unique design is called an unloaded backspan. The result is that the main cables only support the main span, and do not support the spans outside of the towers."

1956 news article about its opening

Jan Danielsen posted
Tom Behringer SB Pool 14 Clinton, Iowa.
[The tow appears to have a second towboat to do bow steering.]

Jen Danielsen posted
Cooperative Venture NB Pool 14 Clinton, Iowa.

Matthew Wong, Mar 2019

Street View

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