US Bridges

US 34 Ml over N Fk Big Thompson River

Fair

Larimer County, Colorado · 11.7 MI E of Estes Park · Structure no. C-15-Y

Built
2003
22 years old
Condition
Fair
inspected September 2023
Type
Box Beam or Girders - Single or Spread
Prestressed Concrete Continuous
Length
145 ft
2 main spans
Daily traffic
4,900
2020 count
Owner
State
State Highway Agency

About this bridge

US 34 Ml over N Fk Big Thompson River is a prestressed concrete continuous box beam or girders - single or spread carrying US 34 Ml over N Fk Big Thompson River in Larimer County, Colorado. It was built in 2003, so it is 22 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 4,900 vehicles a day, roughly 4% of them trucks, projected to reach 5,684 by 2040. The structure is 145 ft (44.3 m) long and 43 ft wide. If it were closed, the detour would be 24.2 mi (39 km).

CarriesUS 34 Ml
CrossesN Fk Big Thompson River
Location11.7 MI E of Estes Park
RouteU.S. Route 34A
Coordinates40.43273, -105.33862
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating39.2 US tons
Inventory rating28.5 US tons

Structure

MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHL 93
Structure length145 ft (44.3 m)
Longest span71 ft (21.7 m)
Deck width43 ft (13.1 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,900 (2020)
Projected traffic5,684 by 2040
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed24.2 mi (39 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 34 Ml over N Fk Big Thompson River built?

It was built in 2003, making it 22 years old in 2025.

What condition is US 34 Ml over N Fk 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 September 2023.

How much traffic does US 34 Ml over N Fk Big Thompson River carry?

About 4,900 vehicles per day (2020 count), of which roughly 4% are trucks.

How long is US 34 Ml over N Fk Big Thompson River?

The structure is 145 ft (44.3 m) long with a longest span of 71 ft (21.7 m) and a deck 43 ft wide.

Who owns US 34 Ml over N Fk Big Thompson River?

It is owned by the State Highway Agency.