US Bridges

Ionia Road over Thornapple River

Good

Eaton County, Michigan · 0.5 MI S of Vermontville · Structure no. 000000000002349

Built
1957
68 years old
Condition
Good
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
112 ft
3 main spans
Daily traffic
2,700
2018 count
Owner
County
County Highway Agency

About this bridge

Ionia Road over Thornapple River is a steel continuous stringer/multi-beam or girder carrying Ionia Road over Thornapple River in Eaton County, Michigan. It was built in 1957, so it is 68 years old, older than the Michigan average of 48.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 2,700 vehicles a day, roughly 2% of them trucks, projected to reach 3,200 by 2038. The structure is 112 ft (34.1 m) long and 29 ft wide. If it were closed, the detour would be 16.2 mi (26 km).

Location

Open in Google Maps
CarriesIonia Road
CrossesThornapple River
Location0.5 MI S of Vermontville
RouteCounty Highway 2313
CountyEaton County
StateMichigan
Coordinates42.61145, -85.02481
Functional classRural Major Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation7: Better than present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating65 US tons
Inventory rating38.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 15
Structure length112 ft (34.1 m)
Longest span44 ft (13.4 m)
Deck width29 ft (8.8 m)
Roadway width27 ft (8.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,700 (2018)
Projected traffic3,200 by 2038
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed16.2 mi (26 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$25,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Ionia Road over Thornapple River built?

It was built in 1957, making it 68 years old in 2025.

What condition is Ionia Road over Thornapple River in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in May 2023.

How much traffic does Ionia Road over Thornapple River carry?

About 2,700 vehicles per day (2018 count), of which roughly 2% are trucks.

How long is Ionia Road over Thornapple River?

The structure is 112 ft (34.1 m) long with a longest span of 44 ft (13.4 m) and a deck 29 ft wide.

Who owns Ionia Road over Thornapple River?

It is owned by the County Highway Agency.