US Bridges

Thornhill RD over Perche CR

Good

Boone County, Missouri · S 7 T 51 N R 13 W · Structure no. 12202

Built
1981
44 years old
Condition
Good
inspected December 2024
Type
Tee Beam
Prestressed Concrete
Length
121 ft
3 main spans
Daily traffic
30
2023 count
Owner
County
County Highway Agency

About this bridge

Thornhill RD over Perche CR is a prestressed concrete tee beam carrying Thornhill RD over Perche CR in Boone County, Missouri. It was built in 1981, so it is 44 years old, younger than the Missouri average of 45.1 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 30 vehicles a day, roughly 10% of them trucks, projected to reach 57 by 2043. The structure is 121 ft (36.9 m) long and 23 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesThornhill RD
CrossesPerche CR
LocationS 7 T 51 N R 13 W
RouteCounty Highway 2
CountyBoone County
StateMissouri
Coordinates39.23114, -92.41939
Functional classRural Local

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating68.5 US tons
Inventory rating42.7 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length121 ft (36.9 m)
Longest span40 ft (12.2 m)
Deck width23 ft (6.9 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30 (2023)
Projected traffic57 by 2043
Trucks10%
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 Thornhill RD over Perche CR built?

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

What condition is Thornhill RD over Perche CR in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in December 2024.

How much traffic does Thornhill RD over Perche CR carry?

About 30 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Thornhill RD over Perche CR?

The structure is 121 ft (36.9 m) long with a longest span of 40 ft (12.2 m) and a deck 23 ft wide.

Who owns Thornhill RD over Perche CR?

It is owned by the County Highway Agency.