US Bridges

I-75 NB over Salt Marsh

Fair

Manatee County, Florida · 2.5MI. South of US-301 · Structure no. 130102

Built
1980
45 years old, rebuilt 2023
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
1,570 ft
26 main spans
Daily traffic
60,250
2023 count
Owner
State
State Highway Agency

About this bridge

I-75 NB over Salt Marsh is a prestressed concrete stringer/multi-beam or girder carrying I-75 NB over Salt Marsh in Manatee County, Florida. It was built in 1980 and reconstructed in 2023, so it is 45 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 60,250 vehicles a day, roughly 13% of them trucks, projected to reach 75,313 by 2042. The structure is 1,570 ft (478.5 m) long and 72 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

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CarriesI-75 NB
CrossesSalt Marsh
Location2.5MI. South of US-301
RouteInterstate 75
CountyManatee County
StateFlorida
Coordinates27.50697, -82.4917
Functional classUrban Principal Arterial - Interstate

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 protection9 ExcellentNo problems noted.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating69 US tons
Inventory rating47.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans26
Design loadUnknown
Structure length1,570 ft (478.5 m)
Longest span60 ft (18.4 m)
Deck width72 ft (21.8 m)
Roadway width69 ft (21 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic60,250 (2023)
Projected traffic75,313 by 2042
Trucks13%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed0.6 mi (1 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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 I-75 NB over Salt Marsh built?

It was built in 1980, making it 45 years old in 2025. It was reconstructed in 2023.

What condition is I-75 NB over Salt Marsh 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 November 2023.

How much traffic does I-75 NB over Salt Marsh carry?

About 60,250 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is I-75 NB over Salt Marsh?

The structure is 1,570 ft (478.5 m) long with a longest span of 60 ft (18.4 m) and a deck 72 ft wide.

Who owns I-75 NB over Salt Marsh?

It is owned by the State Highway Agency.