US 285 South Fork of South Platte Bridge Replacement

Project Facts

  • Cost: $2.6 Million
  • Contractor: Zak Dirt
  • Timeline: May 2021 - Fall 2022
  • Location: US 285 at MP 172.36 in Park County

US 285 S. Platte Project Map

About the Project:

The Colorado Department of Transportation will begin full closures on US 285 over South Fork of South Platte at MP 172.2 to MP 172.5. Access to all local roadways will be maintained during the closure. The off-site detour will utilize CO 9 and US 24. The project is located in Park County on US 285 from MP 172.2 to 173.5.

Zak Dirt Inc. has been selected as the contractor for this project. The project began in late July 2021 and is expected to be completed Fall 2022, weather permitting. Work will require a three month full closure on US 285 with an offsite detour utilizing CO 9 and US 24. The closure will begin July 11 and will remain closed until mid-October.

Work consists of one bridge replacement as well as relieving wetland impacts and redirecting streams. Additionally, the bridge maintenance consists of bridge rail and guardrail
replacement, as well as roadway reconstruction for the bridge approach. This project will benefit motorists by making the bridge safer and improving the driving experience.

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

  • The US 285 bridge replacement project road closure will be open October 18. Travelers will be able to utilize US 285 without closure in place. Full closure of US 285 at MP 172 to MP 172.5
  • Detour to CO 9 and US 24. 

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:

US 285 South Fork project map