US Bridges

US 46 & Blackwell over Granneys Brook

Fair

Morris County, New Jersey · 0.45 Mile West of Nj 15 · Structure no. 1409154

Built
1979
46 years old
Condition
Fair
inspected April 2023
Type
Slab
Prestressed Concrete
Length
35 ft
1 main span
Daily traffic
18,687
2023 count
Owner
State
State Highway Agency

About this bridge

US 46 & Blackwell over Granneys Brook is a prestressed concrete slab carrying US 46 & Blackwell over Granneys Brook in Morris County, New Jersey. It was built in 1979, so it is 46 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 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 18,687 vehicles a day, roughly 4% of them trucks, projected to reach 22,802 by 2043. The structure is 35 ft (10.7 m) long and 122 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesUS 46 & Blackwell
CrossesGranneys Brook
Location0.45 Mile West of Nj 15
RouteU.S. Route 46
CountyMorris County
StateNew Jersey
Coordinates40.88565, -74.56965
Functional classUrban Other Principal 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.
Substructure7 GoodSome minor problems.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry9: Superior to present desirable criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating89 US tons
Inventory rating53 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length35 ft (10.7 m)
Longest span32 ft (9.8 m)
Deck width122 ft (37.2 m)
Roadway width79 ft (24.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,687 (2023)
Projected traffic22,802 by 2043
Trucks4%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost$466,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 46 & Blackwell over Granneys Brook built?

It was built in 1979, making it 46 years old in 2025.

What condition is US 46 & Blackwell over Granneys 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 April 2023.

How much traffic does US 46 & Blackwell over Granneys Brook carry?

About 18,687 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is US 46 & Blackwell over Granneys Brook?

The structure is 35 ft (10.7 m) long with a longest span of 32 ft (9.8 m) and a deck 122 ft wide.

Who owns US 46 & Blackwell over Granneys Brook?

It is owned by the State Highway Agency.