US Bridges

Forest ST over Unnamed Br

Poor

Macon County, Missouri · S 1 T 57 N R 16 W · Structure no. 21431

Built
1987
38 years old
Condition
Poor
inspected January 2024
Type
Slab
Prestressed Concrete Continuous
Length
60 ft
1 main span
Daily traffic
35
2024 count
Owner
County
County Highway Agency

About this bridge

Forest ST over Unnamed Br is a prestressed concrete continuous slab carrying Forest ST over Unnamed Br in Macon County, Missouri. It was built in 1987, so it is 38 years old, younger than the Missouri average of 45.1 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 35 vehicles a day, roughly 10% of them trucks, projected to reach 39 by 2044. The structure is 60 ft (18.3 m) long and 16 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesForest ST
CrossesUnnamed Br
LocationS 1 T 57 N R 16 W
RouteCounty Highway 306
CountyMacon County
StateMissouri
Coordinates39.78155, -92.63514
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
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 rating54.6 US tons
Inventory rating24.8 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans1
Design loadOther
Structure length60 ft (18.3 m)
Longest span39 ft (11.9 m)
Deck width16 ft (5 m)
Roadway width16 ft (4.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic35 (2024)
Projected traffic39 by 2044
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$309,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Forest ST over Unnamed Br built?

It was built in 1987, making it 38 years old in 2025.

What condition is Forest ST over Unnamed Br in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in January 2024.

How much traffic does Forest ST over Unnamed Br carry?

About 35 vehicles per day (2024 count), of which roughly 10% are trucks.

How long is Forest ST over Unnamed Br?

The structure is 60 ft (18.3 m) long with a longest span of 39 ft (11.9 m) and a deck 16 ft wide.

Who owns Forest ST over Unnamed Br?

It is owned by the County Highway Agency.