US Bridges

Nj 31 over South Br. Raritan River

Good

Hunterdon County, New Jersey · 3.43 Mi. N. of Nj 12 JCT · Structure no. 1012156

Built
2003
22 years old
Condition
Good
inspected July 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
274 ft
2 main spans
Daily traffic
27,431
2024 count
Owner
State
State Highway Agency

About this bridge

Nj 31 over South Br. Raritan River is a steel continuous stringer/multi-beam or girder carrying Nj 31 over South Br. Raritan River in Hunterdon County, New Jersey. It was built in 2003, so it is 22 years old, younger than the New Jersey average of 58.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 27,431 vehicles a day, roughly 4% of them trucks, projected to reach 32,917 by 2044. The structure is 274 ft (83.5 m) long and 97 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

CarriesNj 31
CrossesSouth Br. Raritan River
Location3.43 Mi. N. of Nj 12 JCT
RouteState Highway 31
Coordinates40.55069, -74.85298
Functional classUrban Other Principal Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment9: Superior to present desirable criteria
Operating rating61.9 US tons
Inventory rating37 US tons

Structure

MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadUnknown
Structure length274 ft (83.5 m)
Longest span158 ft (48.2 m)
Deck width97 ft (29.6 m)
Roadway width90 ft (27.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic27,431 (2024)
Projected traffic32,917 by 2044
Trucks4%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemYes

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 31 over South Br. Raritan River built?

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

What condition is Nj 31 over South Br. Raritan River in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in July 2024.

How much traffic does Nj 31 over South Br. Raritan River carry?

About 27,431 vehicles per day (2024 count), of which roughly 4% are trucks.

How long is Nj 31 over South Br. Raritan River?

The structure is 274 ft (83.5 m) long with a longest span of 158 ft (48.2 m) and a deck 97 ft wide.

Who owns Nj 31 over South Br. Raritan River?

It is owned by the State Highway Agency.