US Bridges

County Road 13C over Big Thompson River

Fair

Larimer County, Colorado · 0.1 MI N of ST HWY 402A · Structure no. LR13C-0.1-S402A

Built
1983
42 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
109 ft
1 main span
Daily traffic
2,840
2023 count
Owner
County
County Highway Agency

About this bridge

County Road 13C over Big Thompson River is a prestressed concrete stringer/multi-beam or girder carrying County Road 13C over Big Thompson River in Larimer County, Colorado. It was built in 1983, so it is 42 years old, younger 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 6 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 2,840 vehicles a day, roughly 14% of them trucks, projected to reach 3,550 by 2042. The structure is 109 ft (33.3 m) long and 40 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesCounty Road 13C
CrossesBig Thompson River
Location0.1 MI N of ST HWY 402A
RouteCounty Highway 0
CountyLarimer County
StateColorado
Coordinates40.37919, -105.06378
Functional classUrban 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.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating89.6 US tons
Inventory rating43.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length109 ft (33.3 m)
Longest span104 ft (31.7 m)
Deck width40 ft (12.3 m)
Roadway width37 ft (11.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,840 (2023)
Projected traffic3,550 by 2042
Trucks14%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 13C over Big Thompson River built?

It was built in 1983, making it 42 years old in 2025.

What condition is County Road 13C 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 June 2023.

How much traffic does County Road 13C over Big Thompson River carry?

About 2,840 vehicles per day (2023 count), of which roughly 14% are trucks.

How long is County Road 13C over Big Thompson River?

The structure is 109 ft (33.3 m) long with a longest span of 104 ft (31.7 m) and a deck 40 ft wide.

Who owns County Road 13C over Big Thompson River?

It is owned by the County Highway Agency.