Booming Technology Industry Accelerates Construction Schedule for I-15 Upgrades in Utah County
A Thriving Technology Corridor: Tech-Driven Economy Fast-Tracks Modernization of I-15 in Utah County
In Utah County, the Utah Department of Transportation (UDOT) is nearing completion of its I-15 Technology Corridor modernization project. Led by the joint venture team of Ames Construction and Wadsworth Brothers Construction, crews are currently working to complete the final connection – a 4.4-mile freeway section between Lehi Main Street and State Route 92 (Timpanogos Highway).
This portion of the multi-year project, currently running under budget at $415 million, consists of widening the last remaining section of Interstate 15, between Salt Lake City and Spanish Fork, from four to six lanes. These roadway improvements are taking place in a fast-growing metro area known as Silicon Slopes, home to more than 6,500 startup and tech companies.
Other upgrades in this area include: a new overpass to extend Triumph Boulevard over I-15; installation of one-way frontage roads between SR 92 and 2100 North; two fully redesigned interchange systems; improvements to 17 existing bridges (two bridge deck replacements and reconstruction of 15 bridges); two new pedestrian connections over the southbound/northbound frontage roads; and new box culvert structures. Construction activities are anticipated to wrap up in December 2020.
Regional Growth Accelerates Project Schedule
Originally, UDOT planned to begin revamping the area between SR 92 and Lehi Main Street in summer 2020. However, rapid population and business growth in the region spurred transportation officials to advance the construction timeline by two years, resulting in a January 2018 start date.
“A booming technology industry is driving massive growth along the I-15 Technology Corridor, which extends through the burgeoning city of Lehi. As such, our agency’s biggest priority is to expand capacity and improve traffic flow, access and mobility for businesses, their employees and commuters,” says UDOT Project Engineer Boyd Humpherys, PE.
Some of the area’s most prominent companies include IM Flash, a semiconductor manufacturer for Intel and Micron, and tech solution giants Xactware and Oracle. There’s also Adobe, a software developer currently working to double the size of its Lehi-based campus, as well as other noteworthy companies such as Vivint Solar, Ancestry, Podium, and Jane.com.
According to the Utah Economic Council’s 2019 Economic Report to the Governor, 2018 was punctuated by economic increases statewide across all major industrial sectors. Analysts noted Utah’s 3.3 percent pace of job growth ranked highest in the nation, thanks in part to the high-wage positions provided by the professional and business services sector, which includes many high-tech companies.
An Innovative Traffic Control Strategy
A design-build approach is being used to perform infrastructure upgrades between SR 92 and Lehi Main Street. For both UDOT and Ames-Wadsworth, maintaining mobility has been a key focus in all traffic control decision-making.
“The project team has used a number of traditional techniques to maintain access and reduce delays on I-15 and the surrounding side streets – including narrowed lanes and shoulders, reduced speed limits, nighttime lane closures and multiple phasing throughout construction of certain bridges on this project,” says Ernie Green, a Project Manager at Ames Construction. “Our joint venture team has also implemented several innovations, including a maintenance of traffic strategy to provide an additional lane in each direction of I-15 from the onset of construction.”
At the beginning of the project, workers performed temporary mainline widening of the existing four-lane freeway. This tactic created enough space to restripe and implement a five-lane configuration that, in turn, has improved traffic flow and reduced delays during construction.
Key Project Highlights
Freeway expansion has been the major focus of the I-15 Technology Corridor project. On this final connection, new lanes are being added in each direction, for a total of six general purpose lanes and one HOV lane. In addition, crews are reconstructing the existing diverging diamond interchange at SR 92 into a more traditional tight diamond configuration. The 2100 North interchange is also being rebuilt to allow future flyover ramps to connect to the Mountain View Corridor, a 35-mile freeway system under development between I-80 in Salt Lake County and SR 73 in Utah County.
Most of the replacement bridges will be built with 16-1/2-foot clearance – half a foot higher than the national standard. Also, the new Rail Trail Bridge will feature 98-inch-tall, 202-foot-long precast concrete girders – the largest in the state. “This particular bridge design has a really high skew (67 degrees) because the land beneath it may be used for future transit options,” Humpherys explains.
On November 1, 2018, the I-15 Technology Corridor project reached a major milestone when the Triumph Boulevard bridge opened to traffic. “This new bridge offers additional east/west connectivity, allowing for connections to the existing frontage roads and maximizing the capacity of the interchanges at SR 92 and 2100 North,” Green says. One of the replacement bridges, the 600 East crossing of I-15, was also completed in November. Crews are simultaneously working on the other 15 bridges, all of which will be finished next year.
New Frontage Roads Offer Distinct Advantages
While the freeway expansion and bridgework are significant, the development of one-way frontage roads is one of the most unique elements of this Utah project.
“The roadway design utilizes the existing frontage roads to provide more convenient access to the freeway as well as mobility throughout the project. Paired with a series of ‘braided ramp structures,’ the unique design offers more options for commuters and additional entrances and exits to more populated areas,” Green explains.
This series of interchanges will be among the first in Utah to utilize a full frontage-road system in conjunction with mainline I-15. “This offers benefits to commuters who use the corridor for their daily drive, and will be recognized as an advantage to businesses along I-15 that will see ease of access from the freeway,” Green says.
Utility Work Gets Complicated
Early in the project, it became clear that multiple utility lines needed to be relocated to accommodate I-15 widening and construction of the northbound frontage road. Ultimately, the project team decided on joint trenching, a solution that would allow more than half a dozen utilities to move their facilities within the limited right-of-way available.
Though joint trenching could potentially save time and money, it also posed several challenges for the project team. One primary concern involved working within a limited construction area bounded on one side by I-15 traffic and private property owners on the other. Additionally, construction was complicated by the need to protect the utilities in place once they had been relocated. Despite these obstacles, the joint trench was completed successfully last fall.
“Utility installation and roadway construction were further complicated by an elevated water table in the area of 2100 North combined with record-setting wet weather throughout last winter,” adds Greg Lahr, a Project Safety Manager at Ames Construction. “To combat this, a system of wells were drilled to facilitate project site dewatering to lower the water table and create a safe working area for bridge crews and roadway widening.”
A Community-Oriented Mindset
In addition to community forums, UDOT has been keeping the public informed of project activities through social media and its project website, which provides construction updates and features a real-time traffic alert system.
“The community has been supportive of this project because they recognize that it’s needed to alleviate congestion,” Humpherys says. He notes different ways the project team has responded to public concerns – from educating businesses about traffic control solutions that will ease access for their clientele and employees, to installing noise walls out of consideration of residents living near the freeway. Since this is a design-build project, UDOT also had the flexibility to add protected pathways to the project design so that pedestrians and bicyclists could safely cross I-15.
Modernizing the I-15 Technology Corridor certainly reflects UDOT’s aim to “Keep Utah Moving.” By employing innovative solutions that meet growing transportation demands, the agency will no doubt continue to play a vital role in strengthening Utah’s economy and enhancing people’s quality of life.