With the painting of final lane markers on the new roadway, construction at the Interstate 86/Interstate15 "Flying-Y" System Interchange in Pocatello, Idaho, is coming to a successful conclusion.
Begun in July 2022, the three-year $112 million project has dramatically changed the drivability of the interchange, according to the Idaho Transportation Department (ITD). The Sundt-Cannon Joint Venture served as contractors
"We spent over eight years from design to actual construction of the project. We're pretty proud of it," said Aaron Baird, ITD project engineer. "It's one of the bigger projects we've designed. It's one of the largest projects ever designed entirely by ITD staff and inspected with ITD personnel. Most of the people on the team live here locally and this has been a really meaningful project for us to make sure we did our very best."
Critical areas that were improved include the northbound Pocatello Creek on-ramp, the northbound-to-westbound collector distributor, and the eastbound-to-northbound ramp. Each of those improvements made merging from one Interstate to the other smoother and safer for motorists.
"We're excited for people to use the final product. We hope it's something that will last a long time and keep the travelling public safe as they use it," said Greg Roberts, project manager.
The endeavor's scale has been historic.
Approximately 1 million cu. yds. of excavation were completed. In addition, about 490,000 tons of base material was brought in; 116,000 tons of asphalt were placed; and more than 7,700 cu. yds. of concrete were poured. Nearly 70,000 sq. ft. of retaining walls were built throughout the project area. Finally, ITD built eight new bridges. Four of those have precast concrete girders and four have steel girders. In all, more than 5 million lbs. of steel were used in the new bridges.
Construction crews worked year-round and around the clock for approximately three years to complete the project. To minimize disruption to traffic, key demolition operations were conducted at night. These efforts minimized the impact on traffic while the interchange was being reconstructed.
In addition to the major changes inside the Flying-Y design, the Chubbuck Road overpass was reconstructed as an underpass to improve site distances and vertical clearance on I-15, and to improve access to the Wellness Center from Chubbuck. The new underpass is significantly wider and includes bike lanes and sidewalks.
ITD also worked closely with the Portneuf Greenway to construct a pedestrian and bicycle path on the east side of the work site to connect the Greenway to the Wellness Center.
Work left to wrap up the project will be off the roadway and conducted on the shoulders. In addition, ITD will be seeding open ground with native grasses.
"Thank you for being patient with us and seeing our vision, seeing what we're trying to do to positively impact this community," said Zak Johnson, project manager.
