US Bridges

County Road 17 over Big Thompson River

Fair

Weld County, Colorado · 0.9 MI N of CO RD 50 · Structure no. WEL017.0-050.0A

Built
1978
47 years old
Condition
Fair
inspected May 2024
Type
Tee Beam
Prestressed Concrete
Length
148 ft
2 main spans
Daily traffic
48
2023 count
Owner
County
County Highway Agency

About this bridge

County Road 17 over Big Thompson River is a prestressed concrete tee beam carrying County Road 17 over Big Thompson River in Weld County, Colorado. It was built in 1978, 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 48 vehicles a day, roughly 9% of them trucks, projected to reach 68 by 2043. The structure is 148 ft (45.1 m) long and 36 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesCounty Road 17
CrossesBig Thompson River
Location0.9 MI N of CO RD 50
RouteCounty Highway 0
CountyWeld County
StateColorado
Coordinates40.36245, -104.9077
Functional classRural Major Collector

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry9: Superior to present desirable criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating40 US tons
Inventory rating36 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckOther
Main spans2
Design loadHS 20
Structure length148 ft (45.1 m)
Longest span71 ft (21.6 m)
Deck width36 ft (11.1 m)
Roadway width35 ft (10.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic48 (2023)
Projected traffic68 by 2043
Trucks9%
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 17 over Big Thompson River built?

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

What condition is County Road 17 over Big Thompson River 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 May 2024.

How much traffic does County Road 17 over Big Thompson River carry?

About 48 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is County Road 17 over Big Thompson River?

The structure is 148 ft (45.1 m) long with a longest span of 71 ft (21.6 m) and a deck 36 ft wide.

Who owns County Road 17 over Big Thompson River?

It is owned by the County Highway Agency.