US Bridges

Nj 12 over Walnut (mine) Brook

Fair

Hunterdon County, New Jersey · 0.75MI W of 202-31 Circle · Structure no. 1002150

Built
1939
86 years old
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
46 ft
1 main span
Daily traffic
9,811
2023 count
Owner
State
State Highway Agency

About this bridge

Nj 12 over Walnut (mine) Brook is a steel stringer/multi-beam or girder carrying Nj 12 over Walnut (mine) Brook in Hunterdon County, New Jersey. It was built in 1939, so it is 86 years old, older than the New Jersey average of 58.5 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 9,811 vehicles a day, roughly 4% of them trucks, projected to reach 13,851 by 2043. The structure is 46 ft (14 m) long and 50 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesNj 12
CrossesWalnut (mine) Brook
Location0.75MI W of 202-31 Circle
RouteState Highway 12
CountyHunterdon County
StateNew Jersey
Coordinates40.50312, -74.86791
Functional classUrban Minor Arterial

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating68 US tons
Inventory rating40 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length46 ft (14 m)
Longest span41 ft (12.5 m)
Deck width50 ft (15.2 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,811 (2023)
Projected traffic13,851 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 Nj 12 over Walnut (mine) Brook built?

It was built in 1939, making it 86 years old in 2025.

What condition is Nj 12 over Walnut (mine) Brook 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 Nj 12 over Walnut (mine) Brook carry?

About 9,811 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Nj 12 over Walnut (mine) Brook?

The structure is 46 ft (14 m) long with a longest span of 41 ft (12.5 m) and a deck 50 ft wide.

Who owns Nj 12 over Walnut (mine) Brook?

It is owned by the State Highway Agency.