US Bridges

Sidney RD (cr 510) over Flat River

Fair

Montcalm County, Michigan · 0.25 Mi. E. of Johnson RD · Structure no. 000000000007456

Built
1931
94 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
60 ft
1 main span
Daily traffic
4,593
2022 count
Owner
County
County Highway Agency

About this bridge

Sidney RD (cr 510) over Flat River is a steel stringer/multi-beam or girder carrying Sidney RD (cr 510) over Flat River in Montcalm County, Michigan. It was built in 1931, so it is 94 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 4,593 vehicles a day, roughly 7% of them trucks, projected to reach 5,549 by 2042. The structure is 60 ft (18.3 m) long and 30 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesSidney RD (cr 510)
CrossesFlat River
Location0.25 Mi. E. of Johnson RD
RouteCounty Highway 5946
CountyMontcalm County
StateMichigan
Coordinates43.25004, -85.29803
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating62.8 US tons
Inventory rating37.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length60 ft (18.3 m)
Longest span60 ft (18.3 m)
Deck width30 ft (9.1 m)
Roadway width27 ft (8.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,593 (2022)
Projected traffic5,549 by 2042
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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$180,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Sidney RD (cr 510) over Flat River built?

It was built in 1931, making it 94 years old in 2025.

What condition is Sidney RD (cr 510) over Flat 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 September 2023.

How much traffic does Sidney RD (cr 510) over Flat River carry?

About 4,593 vehicles per day (2022 count), of which roughly 7% are trucks.

How long is Sidney RD (cr 510) over Flat River?

The structure is 60 ft (18.3 m) long with a longest span of 60 ft (18.3 m) and a deck 30 ft wide.

Who owns Sidney RD (cr 510) over Flat River?

It is owned by the County Highway Agency.