US Bridges

SR1311 over Cowhorn Swamp

Fair

Onslow County, North Carolina · 1.4 MI N JCT SR1308 · Structure no. 000000001330042

Built
1981
44 years old
Condition
Fair
inspected February 2024
Type
Culvert
Steel
Length
46 ft
3 main spans
Daily traffic
1,300
2019 count
Owner
State
State Highway Agency

About this bridge

SR1311 over Cowhorn Swamp is a steel culvert carrying SR1311 over Cowhorn Swamp in Onslow County, North Carolina. It was built in 1981, so it is 44 years old, older 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 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 1,300 vehicles a day, roughly 6% of them trucks, projected to reach 2,600 by 2040. The structure is 46 ft (14 m) long. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesSR1311
CrossesCowhorn Swamp
Location1.4 MI N JCT SR1308
RouteState Highway 1311
CountyOnslow County
StateNorth Carolina
Coordinates34.89438, -77.51326
Functional classRural Local

Condition and inspection

Fair

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

ComponentRatingMeaning
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionFebruary 2024
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
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating99 US tons
Inventory rating99 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans3
Design loadHS 20 + Mod
Structure length46 ft (14 m)
Longest span11 ft (3.3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,300 (2019)
Projected traffic2,600 by 2040
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 SR1311 over Cowhorn Swamp built?

It was built in 1981, making it 44 years old in 2025.

What condition is SR1311 over Cowhorn 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 February 2024.

How much traffic does SR1311 over Cowhorn Swamp carry?

About 1,300 vehicles per day (2019 count), of which roughly 6% are trucks.

How long is SR1311 over Cowhorn Swamp?

The structure is 46 ft (14 m) long with a longest span of 11 ft (3.3 m).

Who owns SR1311 over Cowhorn Swamp?

It is owned by the State Highway Agency.