US Bridges

County Road 29 over Big Thompson River

Fair

Larimer County, Colorado · Junction With CO RD 22H · Structure no. LR29-0.0-22H

Built
1978
47 years old, rebuilt 2012
Condition
Fair
inspected May 2023
Type
Tee Beam
Prestressed Concrete
Length
77 ft
1 main span
Daily traffic
332
2023 count
Owner
County
County Highway Agency

About this bridge

County Road 29 over Big Thompson River is a prestressed concrete tee beam carrying County Road 29 over Big Thompson River in Larimer County, Colorado. It was built in 1978 and reconstructed in 2012, 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 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 332 vehicles a day, roughly 10% of them trucks, projected to reach 415 by 2042. The structure is 77 ft (23.5 m) long and 34 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesCounty Road 29
CrossesBig Thompson River
LocationJunction With CO RD 22H
RouteCounty Highway 0
CountyLarimer County
StateColorado
Coordinates40.42555, -105.21236
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
Deck8 Very GoodNo problems noted.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating76.8 US tons
Inventory rating50.2 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length77 ft (23.5 m)
Longest span73 ft (22.3 m)
Deck width34 ft (10.4 m)
Roadway width31 ft (9.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic332 (2023)
Projected traffic415 by 2042
Trucks10%
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 29 over Big Thompson River built?

It was built in 1978, making it 47 years old in 2025. It was reconstructed in 2012.

What condition is County Road 29 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 2023.

How much traffic does County Road 29 over Big Thompson River carry?

About 332 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is County Road 29 over Big Thompson River?

The structure is 77 ft (23.5 m) long with a longest span of 73 ft (22.3 m) and a deck 34 ft wide.

Who owns County Road 29 over Big Thompson River?

It is owned by the County Highway Agency.