US Bridges

US 1 (sr 5) over Missouri Little Duck Ch.

Fair

Monroe County, Florida · Little Duck Key (mm 39.6) · Structure no. 900103

Built
1981
44 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
905 ft
11 main spans
Daily traffic
11,300
2024 count
Owner
State
State Highway Agency

About this bridge

US 1 (sr 5) over Missouri Little Duck Ch. is a prestressed concrete stringer/multi-beam or girder carrying US 1 (sr 5) over Missouri Little Duck Ch. in Monroe County, Florida. It was built in 1981, so it is 44 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 11,300 vehicles a day, roughly 17% of them trucks, projected to reach 19,606 by 2044. The structure is 905 ft (275.8 m) long and 47 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesUS 1 (sr 5)
CrossesMissouri Little Duck Ch.
LocationLittle Duck Key (mm 39.6)
RouteU.S. Route 1
CountyMonroe County
StateFlorida
Coordinates24.67878, -81.23513
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating75.7 US tons
Inventory rating44.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans11
Design loadHS 20
Structure length905 ft (275.8 m)
Longest span82 ft (25 m)
Deck width47 ft (14.3 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,300 (2024)
Projected traffic19,606 by 2044
Trucks17%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost$22,000
NavigationNo navigation control on waterway

Frequently asked questions

When was US 1 (sr 5) over Missouri Little Duck Ch. built?

It was built in 1981, making it 44 years old in 2025.

What condition is US 1 (sr 5) over Missouri Little Duck Ch. 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 September 2024.

How much traffic does US 1 (sr 5) over Missouri Little Duck Ch. carry?

About 11,300 vehicles per day (2024 count), of which roughly 17% are trucks.

How long is US 1 (sr 5) over Missouri Little Duck Ch.?

The structure is 905 ft (275.8 m) long with a longest span of 82 ft (25 m) and a deck 47 ft wide.

Who owns US 1 (sr 5) over Missouri Little Duck Ch.?

It is owned by the State Highway Agency.