28th & Pearl Improvement Project

Airport Projects

Broadway Street & Bridge Reconstruction

Ferril Lake at City Park

Foothills Parkway & Arapahoe

Glenwood Canyon

Grand Avenue Paving

Hanging Lake Tunnel

Idaho Springs

Larimer Square

Roundabouts

Santa Fe Dr. & Belleview

Utilities

WYDOT - Gillette/Douglas
HWY 59

	See more photos
	Article from Rocky Mountain Construction (.pdf)

Concrete Works was involved in a truly unique project in Glenwood Canyon in 2007: the repair of an 85-foot long, 1-inch wide crack in the ceiling of the Hanging Lake Tunnel, just east of the maintenance complex, above the eastbound lanes of I-70. CDOT witnessed water leaking through the crack and decided to close the eastbound tunnel on March 30, 2007, and just four days later, Concrete Works was hired to repair the failed structure.

The job was no easy task. The structure itself is 105 feet long and 40 feet wide with approximately 40 feet of dirt and rock above it that needed to be removed before the repair work could even begin.

SDG, Inc. was immediately hired to design the temporary shoring needed to support the failed structure within the tunnel so that the rock and dirt removal could safely begin. By mid-May, 210,000 pounds of structural steel shoring, which included 24 inch beams and 14 inch and 12 inch HP columns, were quickly and successfully installed.

Beginning May 15, rock removal and structural excavation to expose the failed structure began as CDOT finalized the design and details of the repair. The concrete top slab pouring was completed at the end of August and the shotcrete bottom slab was completed on Sept. 17. The reinstallation of the the tunnel ceiling tiles began in mid-September as well. The tunnel was then reopened to eastbound traffic in October. The structure backfilling operation continued with 435 - 16 ft x 4 ft x 2.5 ft blocks of high-density styrofoam placed above the repaired slab. Approximately 3 feet of screened structural fill was then placed on top of the new slab. Ten feet of high-density foam blocks were positioned, after which 5 feet of geogrid reinforced structural backfill was placed above the foam. Backfill design changes significantly lessened the weight of the backfill and provided increased protection from falling rocks. The backfilling operation and drainage pipe installation continued through November.

The 48-inch storm drainage piping and Cinnamon Creek headwall reconfigurations were completed at the end of November. The final seeding and mulching of the disturbed area (1.7 acres), in addition to the removal of all equipment from the site, was completed by the first week in December, just as the first real big snow storm hit.

Article from Colorado Public Works Journal, June 2007 (.pdf)