US Bridges

French Line Road over Smalldon Drain

Fair

Sanilac County, Michigan · Sec 22-27 Watertown Twp · Structure no. 000000000009531

Built
1930
95 years old
Condition
Fair
inspected June 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
24 ft
1 main span
Daily traffic
610
2010 count
Owner
County
County Highway Agency

About this bridge

French Line Road over Smalldon Drain is a steel stringer/multi-beam or girder carrying French Line Road over Smalldon Drain in Sanilac County, Michigan. It was built in 1930, so it is 95 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 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 610 vehicles a day, roughly 10% of them trucks, projected to reach 1,100 by 2030. The structure is 24 ft (7.3 m) long and 32 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesFrench Line Road
CrossesSmalldon Drain
LocationSec 22-27 Watertown Twp
RouteCounty Highway 7438
CountySanilac County
StateMichigan
Coordinates43.36402, -82.79207
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
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 protection8 Very GoodNo problems noted.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating68.9 US tons
Inventory rating41.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length24 ft (7.3 m)
Longest span23 ft (7 m)
Deck width32 ft (9.8 m)
Roadway width31 ft (9.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic610 (2010)
Projected traffic1,100 by 2030
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was French Line Road over Smalldon Drain built?

It was built in 1930, making it 95 years old in 2025.

What condition is French Line Road over Smalldon Drain 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 June 2024.

How much traffic does French Line Road over Smalldon Drain carry?

About 610 vehicles per day (2010 count), of which roughly 10% are trucks.

How long is French Line Road over Smalldon Drain?

The structure is 24 ft (7.3 m) long with a longest span of 23 ft (7 m) and a deck 32 ft wide.

Who owns French Line Road over Smalldon Drain?

It is owned by the County Highway Agency.