Keystone Added to I-74 Arch Bridge

I am usually writing about failed or rotting infrastructure. But not all stories are doom and gloom. Crowds come out to watch crews complete first I-74 bridge arch. The piece was installed May 5th.

The I-74 bridge across the Mississippi River between Illinois and Iowa is old, and in bad shape. To fix that 2 new spans are under construction. True-arch, basket-handle bridges are being built just upstream of the existing bridges. They will carry 4 lanes in each direction.

The bridge joins Bettendorf, Iowa and Moline, Illinois, and is pretty much right in the middle of The Quad Cities region. The other 2 cities are Rock Island, Illinois and Davenport, Iowa. The first span of the existing bridge was built in 1935. A second bridge built to the same design was added in 1961. It is handling almost twice the number of vehicles the design called for, and it is NOT up to interstate highway standards.

While on a tour at the base of the bridge in Bettendorf in May 2012, U.S. Transportation Secretary Ray LaHood said that, in comparison with other bridges that he has seen in other states, the current I-74 Bridge is one of the worst he’s seen.

The keystone, or center piece of the arch, of the first span was put in place during the first week in May. A 100,000 pound chunk of steel. raised about 200 feet in the air. The video at the news story linked at the top of this post is about 2 minutes long, and is not too annoying. Other videos will play after the first video if you take no action.

This is a short video, about 1 minute, from April showing the stage of construction just prior to the keystone being placed. You can see the temporary towers and cables supporting the arch as it is built, and get a feeling for the size and the design. It isn’t my favorite video, but at a minute, it seems to capture what is important. There are more videos, and they are easy enough to find, that are in the 5-6 minute range, taken anytime from January through Easter, if you’re interested in more detailed views of the construction.

You can find an artist’s rendering of the new design at this link.

There is a longer video of the process of getting the keystone in place, but it is 45 minutes, or more, and not particularly interesting. I can’t really recommend it, but I include if for completeness.

3 thoughts on “Keystone Added to I-74 Arch Bridge

  1. When I was at school in the Quads, I rarely used that bridge. Usually used 24th st/Arsenal Bridge or Centennial Bridge. Would have to dig through the files to see if I have any photos of the 74 bridge.

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    • Would be good to keep those photos. The new bridge – both spans – should be done next year, after which they will demolish the old bridge…

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  2. An interesting note, to me anyway, the current webcam view of the bridge shows that the temporary towers are being disassembled. The temporary support cables are down, and the top half of one tower has been removed.

    Now that the first arch is done (mostly) the temporary towers will be rebuilt to support building the 2nd arch.

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