US Bridges

Sth 81 over Flat Rock Creek

Fair

Grant County, Wisconsin · 2.4M E JCT Cth Y · Structure no. B22014000000000

Built
1999
26 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
65 ft
1 main span
Daily traffic
840
2022 count
Owner
State
State Highway Agency

About this bridge

Sth 81 over Flat Rock Creek is a prestressed concrete stringer/multi-beam or girder carrying Sth 81 over Flat Rock Creek in Grant County, Wisconsin. It was built in 1999, so it is 26 years old, younger than the Wisconsin average of 40.3 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 840 vehicles a day, roughly 13% of them trucks, projected to reach 1,250 by 2042. The structure is 65 ft (19.8 m) long and 38 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesSth 81
CrossesFlat Rock Creek
Location2.4M E JCT Cth Y
RouteState Highway 81
CountyGrant County
StateWisconsin
Coordinates42.76761, -90.93598
Functional classRural Minor Arterial

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2023
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 adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating66.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length65 ft (19.8 m)
Longest span61 ft (18.5 m)
Deck width38 ft (11.7 m)
Roadway width35 ft (10.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic840 (2022)
Projected traffic1,250 by 2042
Trucks13%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 Sth 81 over Flat Rock Creek built?

It was built in 1999, making it 26 years old in 2025.

What condition is Sth 81 over Flat Rock Creek 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 2023.

How much traffic does Sth 81 over Flat Rock Creek carry?

About 840 vehicles per day (2022 count), of which roughly 13% are trucks.

How long is Sth 81 over Flat Rock Creek?

The structure is 65 ft (19.8 m) long with a longest span of 61 ft (18.5 m) and a deck 38 ft wide.

Who owns Sth 81 over Flat Rock Creek?

It is owned by the State Highway Agency.