US 285 South Fork of South Platte Bridge Replacement

Travel Alert

Due to the extended closure of I-70, through Glenwood Canyon, CDOT will postpone the planned closure of US 285 between Fairplay and Antero Junction. The postponement will be for a minimum of one week, but a confirmed date has not yet been decided on and depends on when I-70 reopens.

Project Facts

  • Cost: $2.6 Million
  • Contractor: Zak Dirt
  • Timeline: May 2021 - November 2021
  • Location: US 285 at MP 172.36 in Park County

US 285 S. Platte Project Map

About the Project:

This project is located in Region 2 in Park county on US 285 at MP 172.36: Replace Structure H-13-G with H-13- H over the South Fork of the Platte River. Work will require a 3 month full closure of US 285 with an offsite detour utilizing SH 9 and US 24. The work will include rebuilding the approaches to the bridge and replacing the guardrail. It will also include wetland mitigation and a stream diversion utilized to complete the bridge work.

Bridge Condition

The existing structure on US-285 over South Fork South Platte River is routinely monitored by CDOT maintenance staff. During heavy rain this bridge has been periodically closed during high water events for public safety. In addition, a number of the wooden piles exhibit serious rot and decay at the waterline.


Deck: 7 | Superstructure: 6 | Substructure: 4

*The condition of different parts of a structure is rated on a scale of 0 to 9. A top rating of 9 being “excellent” and zero being “failed.” Bridge condition is determined based on the riding surface or deck; the supports immediately beneath the driving surface or superstructure; and the foundation of the supporting posts and piers or the substructure. Bridge ratings are obtained from periodic structure inspections. The structure is classified as “poor” if the lowest rating is less than or equal to 4 out of 9. If a bridge is structurally deficient, there are elements of the structure that need to be monitored and/or repaired. A structurally deficient bridge does not imply that it is likely to collapse or that it is unsafe, it means the structure must be monitored, inspected and repaired/replaced at an appropriate time to maintain its structural integrity.

Traffic Impacts

  • Travelers will encounter a full road closure of US 285 at MP 172.2 to MP 172.5 beginning July 26 and continuing through October. Access to all local roadways will be maintained during the closure. Travelers will utilize the offsite detour on CO 9 and US 24. 
  • Single lane closures and shoulder closures will be in effect at CO 9 at MP 47.57 to MP 47.65, as well as on CO 9 at MP 63.66 to MP 63.73. Motorists are urged to use caution and watch for heavy equipment. At times, through lanes and turn lanes may be temporarily closed to traffic causing brief travel delays. Any temporary closures are to ensure the safety of the workers and the traveling public. Motorists should slow down, drive with caution and give themselves extra travel time.

Notice to Commercial Truckers and Through Travelers on US 50

  • West bound commercial truck drivers and other travelers should be aware of major closures due to the US 50 Little Blue Creek Canyon project, located west of Gunnison. Travel time between Sargents and the Little Blue Creek Canyon closure point is approximately 1.5 hours. Travelers are urged to plan ahead. Visit the project website for more information about the US 50 Little Blue Creek Canyon Project: