US Bridges

Fdr 504 over Narraguinnep Canyon

Fair

Dolores County, Colorado · 11.6 MI on Fdr 504 · Structure no. 021302000001171

Built
1937
88 years old, rebuilt 1960
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
44 ft
1 main span
Daily traffic
20
2003 count
Owner
Federal
U.S. Forest Service

About this bridge

Fdr 504 over Narraguinnep Canyon is a steel stringer/multi-beam or girder carrying Fdr 504 over Narraguinnep Canyon in Dolores County, Colorado. It was built in 1937 and reconstructed in 1960, so it is 88 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 20 vehicles a day, projected to reach 38 by 2013. The structure is 44 ft (13.4 m) long and 26 ft wide. If it were closed, the detour would be 33.6 mi (54 km).

Location

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CarriesFdr 504
CrossesNarraguinnep Canyon
Location11.6 MI on Fdr 504
RouteFederal Lands Road 504
CountyDolores County
StateColorado
Coordinates37.65102, -108.72534
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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating51.5 US tons
Inventory rating39.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length44 ft (13.4 m)
Longest span36 ft (11 m)
Deck width26 ft (8 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20 (2003)
Projected traffic38 by 2013
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed33.6 mi (54 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerU.S. Forest Service
Maintained byU.S. Forest Service
Historic statusHistorical significance not determinable at this time
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$24,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Fdr 504 over Narraguinnep Canyon built?

It was built in 1937, making it 88 years old in 2025. It was reconstructed in 1960.

What condition is Fdr 504 over Narraguinnep Canyon 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 July 2023.

How much traffic does Fdr 504 over Narraguinnep Canyon carry?

About 20 vehicles per day (2003 count).

How long is Fdr 504 over Narraguinnep Canyon?

The structure is 44 ft (13.4 m) long with a longest span of 36 ft (11 m) and a deck 26 ft wide.

Who owns Fdr 504 over Narraguinnep Canyon?

It is owned by the U.S. Forest Service.