The joint venture of Sundt-Cannon recently began pile driving operations for new bridges on the I-86/I-15 System Interchange project in the Pocatello/Chubbuck metropolitan area of Idaho, a significant milestone on the massive $111 million project.
(Photo courtesy of Idaho Transportation Department)
Construction crews are making solid progress on the I-86/I-15 System Interchange project in the Pocatello/Chubbuck metropolitan area of Idaho.
The joint venture of Sundt-Cannon is serving as the general contractor on the project. Crews recently began pile driving piers for the new bridges, a significant milestone on the massive $111 million project, in the beginning of November.
The old interchange was built in the mid-1960s and the aging and obsolete bridges need to be replaced. In addition, Pocatello and Chubbuck have grown significantly to the north of I-86 and east of I-15, resulting in more congestion on the interchange.
"The aging bridges will continue to get closer and closer to the end of their design lifespan," said Project Co-manager Greg Roberts, "They would still be functional, but weight limits would start to have to be imposed on truck traffic. That would negatively impact Pocatello's economic future."
The Chubbuck Road overpass has been closed since August. The project consists of the removal of the existing bridge, excavating new embankments and creating bridges for I-15 to pass over Chubbuck Road. The final Chubbuck Road design will be easier and safer to navigate for motorists, bicyclist and pedestrians.
The area west toward Chubbuck from the Pocatello Creek onramp has been a particularly challenging spot for drivers travelling, which was the catalyst for needed improvements.
"Drivers have just 2,400 feet to move from the right lane to the far left lane to exit to I-86," said District Engineer Todd Hubbard. "This results in difficult maneuvers."
In October, the lowering of the ramp for westbound traffic from northbound I-15 to I-86 was completed and work on building the new bridges commenced. Temporary barriers were put in place at multiple locations and crews prepared lane striping as traffic is shifted away from work areas.
Innovation/Safety
One safety innovation that was implemented was the use of a conveyor belt system to move earth fill from one area of the project to another. The conveyor allows crews to move material without using trucks entering and exiting the Interstate. That makes for a safer work zone for drivers and work crews.
Over the next several weeks, cranes were brought in to and begin drilling shafts for new bridge piers. Excavators and other earthmoving equipment also were working in multiple areas to reprofile the land. Throughout the work zone, water trucks were utilized to keep dust down. Inspectors and engineers also were on site daily ensuring safety and compliance with designs.
This project is partially funded with Transportation Expansion and Congestion Mitigation (TECM) funds as part of Gov. Little's Leading Idaho initiative. The program allows ITD to accelerate project timelines to address rapid growth and build critical infrastructure today that would otherwise take many years to fund and build.
Project Background
When the System Interchange was built, there was almost no development on the east side of I-15. Today, the Highland area has subdivisions, a high school, the fairgrounds and the Wellness Complex. In addition, development at Northgate has already begun and will result in even more traffic.
"We can only expect traffic volume to increase and with it congestion," said Roberts. "That will cause the ‘weave' between the Pocatello Creek onramp and the Chubbuck exit to get worse. Traffic entering, I-15 intending to head toward Chubbuck already has difficulty during peak times crossing all the way to the left to head west on I-86."
The issue for residents now is finding a gap to slip into so they can head west toward Chubbuck.
"That will only get worse if we do nothing," added Johnson, "Gaps between cars will become smaller and smaller making it more difficult to safely merge. Drivers will be forced to make more aggressive lane changes to head to Chubbuck. That kind of situation increases collisions. We don't want to wait until things become dangerous and people get hurt."
ITD also noted an increase in aggressive lane changes and congestion within the interchange, particularly just north of the Pocatello Creek exit. The rapid motion of entering I-15 at Pocatello Creek and crossing to the passing lane to exit toward Chubbuck did not exist when the interchange was built. However, with population growth and associated development that traffic is now significant. Such "exit left" and "enter left" movements do not meet driver expectations, cause confusion, and results in frustration for drivers.
Another much-needed improvement was a redesign of the Chubbuck Road crossing. The old 1962 bridge is narrow and has limited capacity for pedestrians and bicyclists. With the growth of Pocatello and the addition of the Portneuf Wellness Complex, a significant change was needed. ITD's new design changes Chubbuck Road from being an overpass over I-15 to an underpass beneath the freeway with dedicated bike lanes and wider sidewalks. Removal of the bridge also creates more space for the larger project to handle increased traffic.
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