CDOT TWIN TUNNELS CMGC
OVERVIEW
The I-70 Twin Tunnels project involved excavating the eastbound and westbound tunnels along I-70 in order to add an additional lane to the eastbound direction and provide future capacity and mobility improvements for the westbound direction. To minimize the impact of the project to traffic along the I-70 Mountain Corridor, the Colorado Department of Transportation developed an aggressive timeline in order to complete the work, between the months of April – December for a highway detour to be implemented. During this time period, Kraemer-Obayashi completed the tunnel, three miles of highway widening, a new bridge and approximately 4,500-LF of cast-in-place concrete wall to support the future lane, in the first year of the construction. The following year, Kraemer-Obayashi successfully constructed the westbound tunnel and performed a significant surface rock blasting campaign to the immediate east and west of the tunnels. This project was the recipient of a CCA/CDOT CMGC Project Management award and the CCA Environmental Excellence award.
INNOVATIONS
The selection of CMGC delivery method for the project allowed Kraemer-Obayashi to engage earlier in the design and planning process. During the Environmental Assessment, Kraemer Obayashi identified an opportunity to construct an internal access roadway in order to facilitate the movement of excavated tunnel rock to the east end of the project where the primary dump site was located, without impacts to I-70 traffic. The team identified and designed a roadway to permit a one-lane wide, all weather roadway, outside of the interstate detour.