US Bridges

Durnel RD over Hanlon Slough

Fair

Butte County, California · 2.60 MI N of Nelson RD · Structure no. 12C0330

Built
1937
88 years old
Condition
Fair
inspected November 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
55 ft
2 main spans
Daily traffic
44
2019 count
Owner
County
County Highway Agency

About this bridge

Durnel RD over Hanlon Slough is a steel stringer/multi-beam or girder carrying Durnel RD over Hanlon Slough in Butte County, California. It was built in 1937, so it is 88 years old, older than the California average of 54.8 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 44 vehicles a day, roughly 17% of them trucks, projected to reach 116 by 2044. The structure is 55 ft (16.8 m) long and 30 ft wide. If it were closed, the detour would be 11.2 mi (18 km).

Location

Open in Google Maps
CarriesDurnel RD
CrossesHanlon Slough
Location2.60 MI N of Nelson RD
RouteCounty Highway 0
CountyButte County
StateCalifornia
Coordinates39.58854, -121.80044
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 protection7 GoodSome minor problems.
Last inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating110 US tons
Inventory rating70 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadUnknown
Structure length55 ft (16.8 m)
Longest span25 ft (7.6 m)
Deck width30 ft (9.1 m)
Roadway width26 ft (8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic44 (2019)
Projected traffic116 by 2044
Trucks17%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.2 mi (18 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 Durnel RD over Hanlon Slough built?

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

What condition is Durnel RD over Hanlon Slough 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 November 2024.

How much traffic does Durnel RD over Hanlon Slough carry?

About 44 vehicles per day (2019 count), of which roughly 17% are trucks.

How long is Durnel RD over Hanlon Slough?

The structure is 55 ft (16.8 m) long with a longest span of 25 ft (7.6 m) and a deck 30 ft wide.

Who owns Durnel RD over Hanlon Slough?

It is owned by the County Highway Agency.