The Iowa and Illinois Departments of Transportation announced the final piece of the arch for the I-74 River Bridge will be installed on Wednesday, May 6, weather permitting.
Consisting of two connected arch segments, the keystone will complete the basket-handle arch for the Iowa-bound bridge.
The Mississippi River navigation channel will be closed to barge and boat traffic for 72 hours beginning 6 a.m. Wednesday to facilitate work on the arch. All recreational boaters are advised to slow down, obey no-wake zones and avoid the construction zone when possible.
For the health and safety of all involved, the departments of transportation and Lunda Construction Co. encourage the public to witness the milestone from the comfort of their own homes. Those planning to watch in person are asked to follow social distancing and other state and federal guidelines.
“This is a landmark accomplishment for the project, and people want to understandably see it,” said Lunda Construction Co. Vice President Joe A. Larson. “We ask that residents keep everyone’s safety in mind, including our crews working on the bridge.”
The departments of transportation are working with the communities and media to ensure the public can watch the keystone installation from home. The public can view the event from many different angles at the following locations:
- I-74 project webcams (live)
- I-74 Facebook page
- City of Bettendorf Facebook page (live)
- City of Bettendorf YouTube channel (live)
- Local TV news
Installing the last piece of the arch is described by the departments of transportation as a “multi-step process.” They say two arch segments were delivered on site and assembled to form the keystone, weighing approximately 215,000 pounds.
A work platform was also installed below the gap in the arch along with temporary struts and jacks, allowing workers to spread apart the arches prior to setting the keystone. The departments of transportation say numerous surveys have been conducted to determine necessary adjustments in the arch position.
“Surveying is an important part of the process for completing the arch,” said Danielle Alvarez, Project Manager for I-74 and Iowa DOT. “Survey measurements of every angle help determine what adjustments need to be made to facilitate final fit-up. In all, the adjustments to the arch position are anticipated to be under an inch.”
On Wednesday, the largest crane on site will lift the keystone to the top of the arch while ironworkers guide it into place. Once the keystone is set, ironworkers and engineers will take measurements and adjust the position of the keystone to get the perfect fit. Then, the bolting process will begin. There are four connections on the keystone, each requiring over a thousand bolts. Working around the clock, crews will secure the keystone.
The departments of transportation say additional work on the arch, including installing and tensioning the remaining bolts, is anticipated to take several weeks. After the arch is completed, the cable stays on either side will be removed, and the arch will become free standing.
“We are pleased with the progress made this year on the Iowa-bound arch. Our goal is to open the bridge to traffic by the end of 2020,” said Alvarez.