US Bridges

Mn 77 over Minnesota R ; Black Dog

Fair

Hennepin County, Minnesota · 1.0 MI N of JCT TH 13 · Structure no. 9600S

Built
1978
47 years old
Condition
Fair
inspected July 2024
Type
Arch - Thru
Steel
Length
5,185 ft
1 main span
Daily traffic
45,951
2022 count
Owner
State
State Highway Agency

About this bridge

Mn 77 over Minnesota R ; Black Dog is a steel arch - thru carrying Mn 77 over Minnesota R ; Black Dog in Hennepin County, Minnesota. It was built in 1978, so it is 47 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 45,951 vehicles a day, roughly 3% of them trucks, projected to reach 47,500 by 2042. The structure is 5,185 ft (1,580.3 m) long and 60 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

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CarriesMn 77
CrossesMinnesota R ; Black Dog
Location1.0 MI N of JCT TH 13
RouteState Highway 77
CountyHennepin County
StateMinnesota
Coordinates44.82708, -93.2317
Functional classUrban Principal Arterial - Other Freeway or Expressway

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2024
Inspection intervalevery 12 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating64 US tons
Inventory rating38.5 US tons

Structure

Structure typeArch - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+42 approach)
Design loadHS 20 + Mod
Structure length5,185 ft (1,580.3 m)
Longest span360 ft (109.7 m)
Deck width60 ft (18.2 m)
Roadway width56 ft (17.2 m)
Vertical clearance over deck18 ft (5.6 m)

Traffic and service

Average daily traffic45,951 (2022)
Projected traffic47,500 by 2042
Trucks3%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and waterway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemYes

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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was Mn 77 over Minnesota R ; Black Dog built?

It was built in 1978, making it 47 years old in 2025.

What condition is Mn 77 over Minnesota R ; Black Dog 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 Mn 77 over Minnesota R ; Black Dog carry?

About 45,951 vehicles per day (2022 count), of which roughly 3% are trucks.

How long is Mn 77 over Minnesota R ; Black Dog?

The structure is 5,185 ft (1,580.3 m) long with a longest span of 360 ft (109.7 m) and a deck 60 ft wide.

Who owns Mn 77 over Minnesota R ; Black Dog?

It is owned by the State Highway Agency.