US Bridges

Ch 7 FAS 643 over Flat Branch

Fair

Christian County, Illinois · 3.25 MI S Stonington · Structure no. 011331700000000

Built
1983
42 years old
Condition
Fair
inspected November 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
318 ft
3 main spans
Daily traffic
400
2021 count
Owner
County
County Highway Agency

About this bridge

Ch 7 FAS 643 over Flat Branch is a steel continuous stringer/multi-beam or girder carrying Ch 7 FAS 643 over Flat Branch in Christian County, Illinois. It was built in 1983, so it is 42 years old, younger than the Illinois average of 45.3 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 400 vehicles a day, roughly 8% of them trucks, projected to reach 404 by 2046. The structure is 318 ft (96.8 m) long and 27 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesCh 7 FAS 643
CrossesFlat Branch
Location3.25 MI S Stonington
RouteCounty Highway 0
CountyChristian County
StateIllinois
Coordinates39.58628, -89.19504
Functional classRural Minor 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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionNovember 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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating76.1 US tons
Inventory rating45.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length318 ft (96.8 m)
Longest span122 ft (37.2 m)
Deck width27 ft (8.2 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic400 (2021)
Projected traffic404 by 2046
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Ch 7 FAS 643 over Flat Branch built?

It was built in 1983, making it 42 years old in 2025.

What condition is Ch 7 FAS 643 over Flat Branch 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 2024.

How much traffic does Ch 7 FAS 643 over Flat Branch carry?

About 400 vehicles per day (2021 count), of which roughly 8% are trucks.

How long is Ch 7 FAS 643 over Flat Branch?

The structure is 318 ft (96.8 m) long with a longest span of 122 ft (37.2 m) and a deck 27 ft wide.

Who owns Ch 7 FAS 643 over Flat Branch?

It is owned by the County Highway Agency.