US Bridges

SR-312 EB over Matanzas River

Fair

St. Johns County, Florida · S. of St. Augustine · Structure no. 780089

Built
1976
49 years old
Condition
Fair
inspected May 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
3,575 ft
3 main spans
Daily traffic
19,750
2023 count
Owner
State
State Highway Agency

About this bridge

SR-312 EB over Matanzas River is a steel continuous stringer/multi-beam or girder carrying SR-312 EB over Matanzas River in St. Johns County, Florida. It was built in 1976, so it is 49 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 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 19,750 vehicles a day, roughly 2% of them trucks, projected to reach 34,266 by 2045. The structure is 3,575 ft (1,089.7 m) long and 43 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesSR-312 EB
CrossesMatanzas River
LocationS. of St. Augustine
RouteState Highway 312
CountySt. Johns County
StateFlorida
Coordinates29.8671, -81.30698
Functional classUrban 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
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating53 US tons
Inventory rating31.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3 (+34 approach)
Design loadHS 20
Structure length3,575 ft (1,089.7 m)
Longest span170 ft (51.8 m)
Deck width43 ft (13 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic19,750 (2023)
Projected traffic34,266 by 2045
Trucks2%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was SR-312 EB over Matanzas River built?

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

What condition is SR-312 EB over Matanzas 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 May 2024.

How much traffic does SR-312 EB over Matanzas River carry?

About 19,750 vehicles per day (2023 count), of which roughly 2% are trucks.

How long is SR-312 EB over Matanzas River?

The structure is 3,575 ft (1,089.7 m) long with a longest span of 170 ft (51.8 m) and a deck 43 ft wide.

Who owns SR-312 EB over Matanzas River?

It is owned by the State Highway Agency.