US Bridges

US-1 NB (SR-15) over St. Marys River

Fair

Nassau County, Florida · Fl. - Ga. Line · Structure no. 740031

Built
1957
68 years old
Condition
Fair
inspected February 2025
Type
Stringer/Multi-beam or Girder
Steel
Length
382 ft
5 main spans
Daily traffic
5,006
2023 count
Owner
State
State Highway Agency

About this bridge

US-1 NB (SR-15) over St. Marys River is a steel stringer/multi-beam or girder carrying US-1 NB (SR-15) over St. Marys River in Nassau County, Florida. It was built in 1957, so it is 68 years old, older than the Florida average of 41.3 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 5,006 vehicles a day, roughly 9% of them trucks, projected to reach 8,685 by 2045. The structure is 382 ft (116.4 m) long and 34 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesUS-1 NB (SR-15)
CrossesSt. Marys River
LocationFl. - Ga. Line
RouteU.S. Route 1
CountyNassau County
StateFlorida
Coordinates30.77667, -81.97889
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating58.3 US tons
Inventory rating45 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length382 ft (116.4 m)
Longest span77 ft (23.5 m)
Deck width34 ft (10.4 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,006 (2023)
Projected traffic8,685 by 2045
Trucks9%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
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$409,000
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was US-1 NB (SR-15) over St. Marys River built?

It was built in 1957, making it 68 years old in 2025.

What condition is US-1 NB (SR-15) over St. Marys River 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 2025.

How much traffic does US-1 NB (SR-15) over St. Marys River carry?

About 5,006 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is US-1 NB (SR-15) over St. Marys River?

The structure is 382 ft (116.4 m) long with a longest span of 77 ft (23.5 m) and a deck 34 ft wide.

Who owns US-1 NB (SR-15) over St. Marys River?

It is owned by the State Highway Agency.