US Bridges

Sth 122 over Alder Creek

Fair

Iron County, Wisconsin · 1.3M N JCT Sth 77 · Structure no. B26001300000000

Built
1977
48 years old
Condition
Fair
inspected July 2024
Type
Culvert
Concrete Continuous
Length
42 ft
3 main spans
Daily traffic
60
2022 count
Owner
State
State Highway Agency

About this bridge

Sth 122 over Alder Creek is a concrete continuous culvert carrying Sth 122 over Alder Creek in Iron County, Wisconsin. It was built in 1977, so it is 48 years old, older 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 5 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 60 vehicles a day, roughly 6% of them trucks, projected to reach 205 by 2043. The structure is 42 ft (12.7 m) long and 46 ft wide. If it were closed, the detour would be 34.8 mi (56 km).

Location

Open in Google Maps
CarriesSth 122
CrossesAlder Creek
Location1.3M N JCT Sth 77
RouteState Highway 122
CountyIron County
StateWisconsin
Coordinates46.38548, -90.40876
Functional classRural Major 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 protection8 Very GoodNo problems noted.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating71.7 US tons
Inventory rating42.9 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length42 ft (12.7 m)
Longest span11 ft (3.4 m)
Deck width46 ft (14 m)
Roadway width34 ft (10.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic60 (2022)
Projected traffic205 by 2043
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed34.8 mi (56 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 122 over Alder Creek built?

It was built in 1977, making it 48 years old in 2025.

What condition is Sth 122 over Alder 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 July 2024.

How much traffic does Sth 122 over Alder Creek carry?

About 60 vehicles per day (2022 count), of which roughly 6% are trucks.

How long is Sth 122 over Alder Creek?

The structure is 42 ft (12.7 m) long with a longest span of 11 ft (3.4 m) and a deck 46 ft wide.

Who owns Sth 122 over Alder Creek?

It is owned by the State Highway Agency.