I-25 Improvements Between Lincoln and Castle Pines Pkwy, CO

Project Focus
This $28.9 million project on I-25 between Denver and Colorado Springs widens and reconstructs with 309,897 m2 of 320mm thick concrete pavement. This is the second of many important projects required to upgrade this vital corridor.

Project Details
Schedule & Complexity
Although, the traffic control plan required the Contractor to perform all lane closures between the hours of 9:30pm and 5:30am with no work allowed on Friday or Saturday nights, a contract change was made to benefit the project and the users. In order to place the project in the final configuration 10 months ahead of schedule, CDOT elected to allow a delay to traffic on a single Saturday in late November so that bituminous tie-ins could be made in the favorable daylight temperatures permitted by specification. Although this caused a delay of up to one hour for some motorists, the plan resulted in a major overall net reduction in user delays by completing the roadway substantially ahead of schedule. CDOT provided for some Design-Build flexibility in design of the traffic control plan.

Construction & Innovation
The mainline concrete was placed using a Guntert & Zimmerman 850 paver with an automatic dowel bar inserter. A Gomaco 6300 paver and a CMI 350 paver were used at ramps, shoulders and median wall. The Contractor used a Rex Model S central mix plant for phase 1 and a Hagan mixer for phase 2. Haul units were tandem end-dump trucks hauling 8 cy per batch.

The EIS for the corridor was approved while the project was under construction, calling for an 8-lane configuration to be constructed ultimately. CDOT decided that it wanted to take advantage of the detoured traffic and construct the ultimate configuration during this project. A $1.5 million Contract modification was negotiated which included a Design-Build element that was designed and constructed in less than six weeks and will ultimately reduce the delays and costs of the next project.

Quality
A joint team was set up to review the project on a daily basis. The team made recommendations on sign, barrier and attenuator placement, and ensured traffic markings and signs were logical, clean and visible.