US Bridges

M 712 over Amity Creek

Fair

St. Louis County, Minnesota · 1.1 MI N of JCT CSAH12 · Structure no. L8503

Built
1912
113 years old
Condition
Fair
inspected October 2023
Type
Arch - Deck
Concrete
Length
28 ft
1 main span
Daily traffic
77
1985 count
Owner
City
City or Municipal Highway Agency

About this bridge

M 712 over Amity Creek is a concrete arch - deck carrying M 712 over Amity Creek in St. Louis County, Minnesota. It was built in 1912, so it is 113 years old, older than the Minnesota average of 38.5 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 77 vehicles a day, projected to reach 77 by 2029. The structure is 28 ft (8.6 m) long and 22 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesM 712
CrossesAmity Creek
Location1.1 MI N of JCT CSAH12
RouteCity Street 712
CountySt. Louis County
StateMinnesota
Coordinates46.85384, -92.01137
Functional classUrban 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
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionOctober 2023
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 geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment4: Meets minimum tolerable limits to be left in place as is
Operating rating54 US tons
Inventory rating36 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckNot applicable
Main spans1
Design loadUnknown
Structure length28 ft (8.6 m)
Longest span28 ft (8.6 m)
Deck width22 ft (6.6 m)
Roadway width17 ft (5.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic77 (1985)
Projected traffic77 by 2029
Trucks—
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusEligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was M 712 over Amity Creek built?

It was built in 1912, making it 113 years old in 2025.

What condition is M 712 over Amity 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 October 2023.

How much traffic does M 712 over Amity Creek carry?

About 77 vehicles per day (1985 count).

How long is M 712 over Amity Creek?

The structure is 28 ft (8.6 m) long with a longest span of 28 ft (8.6 m) and a deck 22 ft wide.

Who owns M 712 over Amity Creek?

It is owned by the City or Municipal Highway Agency.