New I-75 Bridge over Mississippi River at Molene/Bettendorf

(original I-74 bridges, Webcam, satellite is below)

The $1.2 billion dollar project not only includes the new bridge, it includes a lot of road work on both sides of the river. Quite a few buildings were torn down, including a depot, in Bettendorf, IA for a new road alignment. A bed containing about 450,000 mussels had to be moved before the piers could be built.

Screenshot from Presentation on  Materials

Satellite

I'm using Bing instead of Google because Google is not showing any activity yet.

This crane photo is what let me know that construction had started on the replacement bridge and that it was time to reasearch the new bridge again.

Matt Saddoris commented on a posting, cropped
Ben Stalvey Micheles MLC 300?
Matt Saddoris Maxim Moline, Illinois

Map from Materials

Before they built the dam a couple of miles downstream from here, this stretch of the river must have been a rapids. That means the river scoured the bottom down to bedrock. So they are buildings piers keyed into the bedrock that can withstand the lateral forces of a true arch. Since it is a true arch rather than a tied arch, they don't have the option of building the arch near a shore and floating it into place like they did, for example, the Eggner Ferry Bridge. To keep the navigation channel open, they are using back stays to build the arches with 35' to 65' steel segments.

ShoolPresentation from Materials, p15

Beginning this fall or early winter [2018], crews will begin lifting the 35- to 65-foot steel segments into place. Currently, the steel segments are being fabricated at a plant in Gary, Ind., after which they will be trucked to the Quad-Cities, said Danielle Alvarez, the I-74 project manager with the Iowa Department of Transportation....Cable stays will be used to hold the segments into place, while the rest of the segments are raised and fitted together. There will actually be two arches in each direction on the new bridge, angling inward to form a pair of basket handles....Alvarez said the tied-arch design at Talbot Memorial Bridge (Centennial) between Davenport and Rock Island is more of typical of Mississippi River crossings, but the relatively shallow water depth and rock elevations under I-74 allowed for the new bridge to be a true-arch design. The cost of the steel fabrication, as well as putting the segments into place, is $17 million for both spans, according to the Iowa DOT. [ArchIsNextStep]

I have not been able to find construction photos of the arch construction.

The "Y" part of the piers looked like they could be precast "trophies" similar to the ones used for the new Pensacola Bay Bridge. But these photos shows they built the piers in place.

ShoolPresentation from Materials, p22

ShoolPresentation from Materials, p22

Roads & Bridges

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