US Bridges

Grayrock Road over So. Branch Raritan River

Good

Hunterdon County, New Jersey · 0.3 Mi. East of Nj 31 · Structure no. 10XXC76

Built
1993
32 years old
Condition
Good
inspected March 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
119 ft
1 main span
Daily traffic
1,932
2023 count
Owner
County
County Highway Agency

About this bridge

Grayrock Road over So. Branch Raritan River is a steel stringer/multi-beam or girder carrying Grayrock Road over So. Branch Raritan River in Hunterdon County, New Jersey. It was built in 1993, so it is 32 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 1,932 vehicles a day, roughly 1% of them trucks, projected to reach 2,358 by 2043. The structure is 119 ft (36.3 m) long and 35 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesGrayrock Road
CrossesSo. Branch Raritan River
Location0.3 Mi. East of Nj 31
CountyHunterdon County
StateNew Jersey
Coordinates40.65614, -74.90794
Functional classUrban Local

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating110.1 US tons
Inventory rating83 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length119 ft (36.3 m)
Longest span114 ft (34.7 m)
Deck width35 ft (10.8 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,932 (2023)
Projected traffic2,358 by 2043
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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 Grayrock Road over So. Branch Raritan River built?

It was built in 1993, making it 32 years old in 2025.

What condition is Grayrock Road over So. Branch 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 March 2023.

How much traffic does Grayrock Road over So. Branch Raritan River carry?

About 1,932 vehicles per day (2023 count), of which roughly 1% are trucks.

How long is Grayrock Road over So. Branch Raritan River?

The structure is 119 ft (36.3 m) long with a longest span of 114 ft (34.7 m) and a deck 35 ft wide.

Who owns Grayrock Road over So. Branch Raritan River?

It is owned by the County Highway Agency.