Project Update: Bridge restoration on US 50 Frontage Road in Gunnison funded through the Colorado Bridge Enterprise

GUNNISON COUNTY – The Colorado Department of Transportation and contractor SEMA Construction began a project last September 2011 to restore the “twin bridges” on the US 50 frontage road on the west side of Gunnison (near mile marker 155). The project was scheduled in two phases to allow crews to work in the river during the fall when the Gunnison River was a low flow. The work was suspended for the winter and is back underway now, with the project wrapping up by late August.

The bridges—which were built in 1926—are rated in “poor” condition and are listed on CDOT’s statewide *FASTER Bridge Enterprise Projects list. The two steel truss, single-span bridges are located on the east-west US 50 frontage road (which runs parallel to US 50 on the north side) The east bridge structure is built over the main channel of the Gunnison River and the west structure is built over the river’s overflow channel.

The east structure during the first phase received a full reinforcement of its two abutments (where bridge meets land) to strengthen them for a 500-year flood event. The concrete decks on both structures have been replaced with about nine inches of new concrete and, during this second phase, will also receive a water-proofing membrane followed by two inches of asphalt.

Currently, the main bridge is covered with a tent (made of the same material as a parachute) to enable crews to sandblast the old lead-based paint from the steel truss structure and paint it without impacts to the environment. The steel grit sandblasting material, as well as the paint, is vacuumed inside the tent in one single process; then paint debris and sandblast material become separated so the former can be disposed of properly and the latter can be recycled. A temporary deck made of corrugated steel was laid over cables and suspended above the concrete deck—the tent is attached at the bottom to this temporary deck. This was done to ensure no lead paint or sandblast particles reach the bridge’s deck.

A health and safety inspector is on site at all times monitoring the air and all procedures to ensure the tent and vacuum system are doing their jobs. The bridges are being painted with the same silver as before, maintaining the color and overall appearance of these historic structures. Once painting is complete on the main channel bridge (likely the by the end of June), crews will move operations to the second bridge. After painting, the deck work will resume.

TRAVEL IMPACTS: Both bridges are closed 24/7 through this August 2012. Fortunately, there is access to adjoining properties from either side of the bridges—motorists and cyclists will need to utilize US 50 as a short, quarter-mile detour. CDOT is urging motorists to take care near cyclists, who will now be sharing the highway along this section more frequently.

This project was contracted to SEMA Construction of Centennial, CO, for $2 million, all of which is being funded through the Colorado Bridge Enterprise.

For information on other CDOT projects statewide, the public may log on to www.cotrip.org or call 511. Better yet, log onto CDOT’s web site at www.coloradodot.info and sign up to receive FREE e-mail or wireless text messages about road conditions in your chosen area.

*The Colorado Bridge Enterprise (CBE) was formed in 2009 as part of the FASTER (Funding Advancement for Surface Transportation and Economic Recovery) legislation. It operates as a government-owned business within the Colorado Department of Transportation. The Colorado Transportation Commission serves as the Colorado Bridge Enterprise Board. The purpose of the CBE is to finance, repair, reconstruct and replace bridges designated as structurally deficient or functionally obsolete, and rated “poor." In order to accomplish this goal, a bridge safety surcharge ranging from $13 to $32 has been imposed on vehicle registration based upon vehicle weight. Revenues from the bridge safety surcharge fee are phased in over a three-year period, and are estimated to generate approximately $100 million in annual funding. For more information, log onto: http://www.coloradodot.info/programs/BridgeEnterprise.