This complex, impactful project took home the 2024 Construction Risk Partners Build America Grand Award
BY CHRISTINE PREUSLER
In the history of the Colorado Department of Transportation (CDOT), one effort stands as a colossus among its peers: the Central 70 Project.
The public-private partnership (P3) between CDOT and Kiewit Infrastructure Co., a member of multiple AGC chapters, reconstructed an 11-mile stretch of I-70 — once a bottleneck for Denver’s bustling community — from six lanes to 10. The design-build-finance-operate-maintain project also included adding new express and general-purpose lanes in each direction, removing and replacing bridges, removing a half-century-old viaduct, lowering a section of the interstate below ground level, and placing a park over the lowered portion of the interstate.
Equally impressive was Kiewit’s execution of a highly complex traffic control phasing sequence that allowed 200,000 vehicles to keep moving through the construction zone daily while reducing traffic accidents by 40%. Today, the project continues to reduce congestion and improve safety while leaving room for future transportation growth.
Despite being the largest single project in CDOT’s history and one of the most technologically advanced interstatewidening and Intelligent Transportation System (ITS) projects in the United States, Kiewit met CDOT’s schedule and budget while honoring commitments to the community and environment.
For these reasons, among others, the Central 70 Project was given the 2024 Construction Risk Partners Build America Grand Award from AGC of America during its Annual Convention in San Diego, earlier this year.
Overcoming Challenges
While transformative for Colorado’s infrastructure, the Central 70 Project required Kiewit to overcome several significant challenges, from reducing community impact to navigating construction complexity. In addition, Kiewit had to successfully address the needs of various stakeholders, including CDOT, the traveling public, local community members, schools and governments, a network of utilities and owners and private business interests.
Dividing the project into three sections allowed Kiewit to address various challenges effectively. The eastern section of the project focused on widening, with comprehensive reconstruction of the interstate and frontage roads in the center section. Work on the lowered section — which included descending below grade and transforming an aging viaduct into modern infrastructure complete with a four-acre park — showcased the project’s ingenuity.
Kiewit Area Manager Jason Proskovec said removing the structurally deficient and functionally obsolete viaduct was a feat of engineering in itself.
“[Demolishing] the aging viaduct was unique; it was right next to residential areas and businesses for a mile long,” he said.
Kiewit used advanced misting and spraying systems to minimize dust during the demolition of the concrete viaduct. Its removal helped reconnect the community — as did the addition of the park, complete with a sports field, covered stage area, splash pad, community center and playground.
Environmental considerations surrounding the project brought forth additional challenges.
“What a unique project this was — dealing with naturally contaminated groundwater and building a pump station that handled all the stormwater in a lowered section,” Proskovec said.
Kiewit teams, assisted by specialized subcontractors, deployed various control measures to tackle erosion and sediment control issues. Vigilant monitoring and maintenance of these systems followed each weather event to reduce adverse effects on nearby waterways. Additionally, designated construction access points equipped with tracking pads were established and enforced to keep mud and dirt at bay.
Kiewit enacted swift response protocols to manage potential spills of oil, fuel and other contaminants. This involved placing large spill kits in operational areas and furnishing field supervisors with smaller spill kits tailored for vehicle storage. Furthermore, Kiewit established agreements and contracts to guarantee prompt specialized assistance for hazardous material encounters or spills, ensuring access to training and resources.
The Central 70 Project is also a testament to safety done right. Rigorous environmental monitoring and safety measures were implemented to ensure the safety of Swansea Elementary School, which was close to construction. These measures included erecting a noise mitigation and safety wall to separate the school from the construction site. Continuous monitoring and maintenance of safe access to the school were upheld throughout the project.
Solid obstacles shielded pedestrian pathways, while the walkway within project boundaries underwent regular upkeep, including snow removal and deicing. To ensure community safety, the team also facilitated transportation for locals and students around construction areas that presented temporary safety risks for pedestrians.
Overall, the Central 70 Project showcased the collaboration of various disciplines and professionals to deliver a high-quality product within budget and on schedule while meeting environmental compliance and community needs.
“Every time I drive through this project with my kids, I’m like, I built that,” said Pete Remington, construction manager, Kiewit. “It’s really important to showcase [the work we have done] because everybody involved in this project is really proud of what we built.”
Proskovec agreed.
“It’s important for the AGC to recognize awesome builds like this because, as contractors, we’re all competitive, and these types of awards help the industry to keep raising the bar,” he said. “It really just makes all of us better as contractors — more innovative, and, ultimately, more successful.”
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