US Bridges

NC111 over Back Swamp

Fair

Onslow County, North Carolina · 0.1 MI.W.JCT.SR1209 · Structure no. 000000001330061

Built
1994
31 years old
Condition
Fair
inspected January 2024
Type
Slab
Prestressed Concrete
Length
72 ft
2 main spans
Daily traffic
2,500
2021 count
Owner
State
State Highway Agency

About this bridge

NC111 over Back Swamp is a prestressed concrete slab carrying NC111 over Back Swamp in Onslow County, North Carolina. It was built in 1994, so it is 31 years old, younger than the North Carolina average of 38.7 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 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 2,500 vehicles a day, roughly 7% of them trucks, projected to reach 5,000 by 2040. The structure is 72 ft (21.9 m) long and 36 ft wide. If it were closed, the detour would be 2.5 mi (4 km).

Location

Open in Google Maps
CarriesNC111
CrossesBack Swamp
Location0.1 MI.W.JCT.SR1209
RouteState Highway 111
CountyOnslow County
StateNorth Carolina
Coordinates34.83456, -77.63659
Functional classRural 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
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating99 US tons
Inventory rating62.9 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans2
Design loadHS 20 + Mod
Structure length72 ft (21.9 m)
Longest span34 ft (10.3 m)
Deck width36 ft (10.9 m)
Roadway width32 ft (9.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,500 (2021)
Projected traffic5,000 by 2040
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed2.5 mi (4 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 NC111 over Back Swamp built?

It was built in 1994, making it 31 years old in 2025.

What condition is NC111 over Back Swamp 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 January 2024.

How much traffic does NC111 over Back Swamp carry?

About 2,500 vehicles per day (2021 count), of which roughly 7% are trucks.

How long is NC111 over Back Swamp?

The structure is 72 ft (21.9 m) long with a longest span of 34 ft (10.3 m) and a deck 36 ft wide.

Who owns NC111 over Back Swamp?

It is owned by the State Highway Agency.