US Bridges

US1NBL over Seaboard RR

Poor

Wake County, North Carolina · 1.3MI S JCT US1A · Structure no. 000000001830312

Built
1941
84 years old
Condition
Poor
inspected March 2023
Type
Tee Beam
Concrete
Length
209 ft
5 main spans
Daily traffic
45,500
2021 count
Owner
State
State Highway Agency

About this bridge

US1NBL over Seaboard RR is a concrete tee beam carrying US1NBL over Seaboard RR in Wake County, North Carolina. It was built in 1941, so it is 84 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 poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 45,500 vehicles a day, roughly 12% of them trucks, projected to reach 91,000 by 2040. The structure is 209 ft (63.7 m) long and 39 ft wide. If it were closed, the detour would be 2.5 mi (4 km).

Location

Open in Google Maps
CarriesUS1NBL
CrossesSeaboard RR
Location1.3MI S JCT US1A
RouteU.S. Route 1
CountyWake County
StateNorth Carolina
Coordinates35.9256, -78.54281
Functional classUrban Other Principal Arterial

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating51.9 US tons
Inventory rating31 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans5
Design loadH 15
Structure length209 ft (63.7 m)
Longest span56 ft (17 m)
Deck width39 ft (12 m)
Roadway width36 ft (10.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic45,500 (2021)
Projected traffic91,000 by 2040
Trucks12%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
Detour if closed2.5 mi (4 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkNon-Interstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was US1NBL over Seaboard RR built?

It was built in 1941, making it 84 years old in 2025.

What condition is US1NBL over Seaboard RR in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in March 2023.

How much traffic does US1NBL over Seaboard RR carry?

About 45,500 vehicles per day (2021 count), of which roughly 12% are trucks.

How long is US1NBL over Seaboard RR?

The structure is 209 ft (63.7 m) long with a longest span of 56 ft (17 m) and a deck 39 ft wide.

Who owns US1NBL over Seaboard RR?

It is owned by the State Highway Agency.