US Bridges

County Road 20.5 over Boulder Creek

Fair

Weld County, Colorado · 1.8 MI E of CO RD 1 · Structure no. WEL020.5-003.0B

Built
1978
47 years old, rebuilt 2010
Condition
Fair
inspected June 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
133 ft
2 main spans
Daily traffic
3,015
2022 count
Owner
County
County Highway Agency

About this bridge

County Road 20.5 over Boulder Creek is a steel stringer/multi-beam or girder carrying County Road 20.5 over Boulder Creek in Weld County, Colorado. It was built in 1978 and reconstructed in 2010, so it is 47 years old, older than the Colorado average of 42.2 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 3,015 vehicles a day, roughly 20% of them trucks, projected to reach 4,281 by 2042. The structure is 133 ft (40.4 m) long and 32 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesCounty Road 20.5
CrossesBoulder Creek
Location1.8 MI E of CO RD 1
RouteCounty Highway 0
CountyWeld County
StateColorado
Coordinates40.13875, -105.02014
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating35.4 US tons
Inventory rating21.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckCorrugated steel
Main spans2
Design loadHS 20
Structure length133 ft (40.4 m)
Longest span62 ft (19 m)
Deck width32 ft (9.8 m)
Roadway width31 ft (9.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,015 (2022)
Projected traffic4,281 by 2042
Trucks20%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was County Road 20.5 over Boulder Creek built?

It was built in 1978, making it 47 years old in 2025. It was reconstructed in 2010.

What condition is County Road 20.5 over Boulder Creek in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in June 2024.

How much traffic does County Road 20.5 over Boulder Creek carry?

About 3,015 vehicles per day (2022 count), of which roughly 20% are trucks.

How long is County Road 20.5 over Boulder Creek?

The structure is 133 ft (40.4 m) long with a longest span of 62 ft (19 m) and a deck 32 ft wide.

Who owns County Road 20.5 over Boulder Creek?

It is owned by the County Highway Agency.