US Bridges

Mast Road over Huron River

Fair

Washtenaw County, Michigan · Webster Twp Sec 31 · Structure no. 000000000010996

Built
1976
49 years old
Condition
Fair
inspected April 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
183 ft
3 main spans
Daily traffic
10,929
2020 count
Owner
County
County Highway Agency

About this bridge

Mast Road over Huron River is a prestressed concrete stringer/multi-beam or girder carrying Mast Road over Huron River in Washtenaw County, Michigan. It was built in 1976, so it is 49 years old, older than the Michigan average of 48.3 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 10,929 vehicles a day, roughly 9% of them trucks, projected to reach 16,240 by 2040. The structure is 183 ft (55.8 m) long and 59 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesMast Road
CrossesHuron River
LocationWebster Twp Sec 31
RouteCounty Highway 8143
CountyWashtenaw County
StateMichigan
Coordinates42.34134, -83.87962
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 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 geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating77.5 US tons
Inventory rating46.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length183 ft (55.8 m)
Longest span61 ft (18.6 m)
Deck width59 ft (18.1 m)
Roadway width47 ft (14.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,929 (2020)
Projected traffic16,240 by 2040
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$700,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Mast Road over Huron River built?

It was built in 1976, making it 49 years old in 2025.

What condition is Mast Road over Huron River 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 April 2024.

How much traffic does Mast Road over Huron River carry?

About 10,929 vehicles per day (2020 count), of which roughly 9% are trucks.

How long is Mast Road over Huron River?

The structure is 183 ft (55.8 m) long with a longest span of 61 ft (18.6 m) and a deck 59 ft wide.

Who owns Mast Road over Huron River?

It is owned by the County Highway Agency.