US Bridges

Sth 70 over Clam Lake Narrows

Fair

Burnett County, Wisconsin · 1.8M E JCT Sth 35 to N · Structure no. B07003200000000

Built
1993
32 years old
Condition
Fair
inspected September 2024
Type
Slab
Concrete Continuous
Length
86 ft
3 main spans
Daily traffic
4,400
2023 count
Owner
State
State Highway Agency

About this bridge

Sth 70 over Clam Lake Narrows is a concrete continuous slab carrying Sth 70 over Clam Lake Narrows in Burnett County, Wisconsin. It was built in 1993, so it is 32 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 4,400 vehicles a day, roughly 6% of them trucks, projected to reach 7,320 by 2043. The structure is 86 ft (26.3 m) long and 47 ft wide. If it were closed, the detour would be 38.5 mi (62 km).

Location

Open in Google Maps
CarriesSth 70
CrossesClam Lake Narrows
Location1.8M E JCT Sth 35 to N
RouteState Highway 70
CountyBurnett County
StateWisconsin
Coordinates45.81899, -92.3283
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 protection8 Very GoodNo problems noted.
Last inspectionSeptember 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 geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating73.9 US tons
Inventory rating44.6 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length86 ft (26.3 m)
Longest span32 ft (9.9 m)
Deck width47 ft (14.3 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,400 (2023)
Projected traffic7,320 by 2043
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed38.5 mi (62 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 70 over Clam Lake Narrows built?

It was built in 1993, making it 32 years old in 2025.

What condition is Sth 70 over Clam Lake Narrows 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 2024.

How much traffic does Sth 70 over Clam Lake Narrows carry?

About 4,400 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is Sth 70 over Clam Lake Narrows?

The structure is 86 ft (26.3 m) long with a longest span of 32 ft (9.9 m) and a deck 47 ft wide.

Who owns Sth 70 over Clam Lake Narrows?

It is owned by the State Highway Agency.