US Bridges

NC171 over Lanier Swamp

Fair

Martin County, North Carolina · 0.2 MI.N.JCT.SR1538 · Structure no. 000000001170026

Built
1976
49 years old
Condition
Fair
inspected March 2024
Type
Slab
Prestressed Concrete
Length
45 ft
1 main span
Daily traffic
2,200
2022 count
Owner
State
State Highway Agency

About this bridge

NC171 over Lanier Swamp is a prestressed concrete slab carrying NC171 over Lanier Swamp in Martin County, North Carolina. It was built in 1976, so it is 49 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 2,200 vehicles a day, roughly 7% of them trucks, projected to reach 4,400 by 2040. The structure is 45 ft (13.7 m) long and 36 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesNC171
CrossesLanier Swamp
Location0.2 MI.N.JCT.SR1538
RouteState Highway 171
CountyMartin County
StateNorth Carolina
Coordinates35.78541, -76.90687
Functional classRural Major Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 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
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48 US tons
Inventory rating28 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHS 20 + Mod
Structure length45 ft (13.7 m)
Longest span44 ft (13.4 m)
Deck width36 ft (10.9 m)
Roadway width35 ft (10.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,200 (2022)
Projected traffic4,400 by 2040
Trucks7%
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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was NC171 over Lanier Swamp built?

It was built in 1976, making it 49 years old in 2025.

What condition is NC171 over Lanier 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 March 2024.

How much traffic does NC171 over Lanier Swamp carry?

About 2,200 vehicles per day (2022 count), of which roughly 7% are trucks.

How long is NC171 over Lanier Swamp?

The structure is 45 ft (13.7 m) long with a longest span of 44 ft (13.4 m) and a deck 36 ft wide.

Who owns NC171 over Lanier Swamp?

It is owned by the State Highway Agency.