US Bridges

18th Ave South over Clam Bayou

Fair

Pinellas County, Florida · 140FT W of 42nd Street S · Structure no. 157133

Built
1990
35 years old
Condition
Fair
inspected May 2023
Type
Culvert
Concrete
Length
22 ft
2 main spans
Daily traffic
5,800
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

18th Ave South over Clam Bayou is a concrete culvert carrying 18th Ave South over Clam Bayou in Pinellas County, Florida. It was built in 1990, so it is 35 years old, younger 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 5,800 vehicles a day, roughly 4% of them trucks, projected to reach 10,063 by 2042. The structure is 22 ft (6.6 m) long. If it were closed, the detour would be 1.9 mi (3 km).

Location

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Carries18th Ave South
CrossesClam Bayou
Location140FT W of 42nd Street S
RouteCity Street 0
CountyPinellas County
StateFlorida
Coordinates27.75196, -82.69037
Functional classUrban Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating60.8 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadHS 20
Structure length22 ft (6.6 m)
Longest span10 ft (3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,800 (2023)
Projected traffic10,063 by 2042
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 18th Ave South over Clam Bayou built?

It was built in 1990, making it 35 years old in 2025.

What condition is 18th Ave South over Clam Bayou 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 2023.

How much traffic does 18th Ave South over Clam Bayou carry?

About 5,800 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is 18th Ave South over Clam Bayou?

The structure is 22 ft (6.6 m) long with a longest span of 10 ft (3 m).

Who owns 18th Ave South over Clam Bayou?

It is owned by the City or Municipal Highway Agency.