SH 82 Critical Culverts – Independence Pass, Colorado

CDOT identified a failed 42” corrugated steel culvert underneath State Highway 82 (Independence Pass) that links Twin Lakes to Aspen. The project was to be built between August and November during the height of the tourist season. The remote mountain location with no cell service demanded that all work be coordinated and planned in a detailed and precise manner to keep the project on schedule. AWC completed the project ahead of schedule as a result of the coordination and pre-planning efforts of the project team.

The project included installing a precast 8’ x 6’ crete box culvert with cast-in-place wing walls and an inlet structure, reconstructing the roadway, creating a pond and overflow channel, and landscaping of the site in a very tight work area. The new culvert, complete with fish ladders, would connect Echo Creek with Lake Creek, a popular fishing area.

AWC mobilized to the site in August of 2014 and constructed the project in two phases. The first task was to divert Echo Creek around the work area. The high country snowpack was still evident in August, and a greater volume of water than originally anticipated needed to be diverted. AWC diverted the water quickly, then widened the roadway to allow for a single lane of traffic to travel adjacent to the work area. To support the roadway and create a safe work area, vertical micro-piles were drilled through center of the roadway bed to create an engineered shoring system, allowing the crew to excavate for the box and work immediately adjacent to the roadway. The south segments of the box were set in place, and the cast-in-place wing walls and headwalls were then formed and poured. As part of the backfill on the south side, an engineered geo-synthetic wall was built adjacent to the open roadway, which enabled vertical excavation on the north side of the road, allowing for the installation of the remaining box segments.

Once the roadway was repaved and traffic was shifted to the south side of the road, AWC was able to excavate for the north portion of the box. Managing the north side of the excavation was challenging, due to substantial groundwater and alluvial soils. Once the water was controlled, AWC was able to complete the box installation, build the wing walls and inlet structure, and complete structural backfill. Paving was completed in late October, allowing landscaping to be completed before winter.