Structure 2397 · Eaton County, MI

Bunker Highway over Grand River

Carries Bunker Highway over Grand River, 2.3 Mi NE Of Eaton Rapids.

Overall conditionFair

Set by its lowest-rated component: Deck at 6 of 9.

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure7/9 · Good
Substructure7/9 · Good
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT160 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 7/9

160 ft end to end, longest span 68 ft: about 2 semi-trucks nose to tail. Lengths and the semi-truck on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a box-beam bridge.

Built199432 years old
Length159.8 ft48.7 m
Daily traffic246counted 2014
Last inspectedJuly 2023every 24 months

Location

StateMichigan
CountyEaton
Location2.3 Mi NE Of Eaton Rapids
CarriesBunker Highway
CrossesGrand River
Coordinates42.55304, -84.62169

Physical Characteristics

MaterialPrestressed Concrete
DesignBox Beam - Multiple
Total Length159.8 ft (48.7 m)
Max Span67.9 ft (20.7 m)
Deck Width32.8 ft (10 m)
Deck Area487 sq m
Main Spans3
Year Built1994

Traffic

Avg Daily Traffic246 (2014)
Lanes On Bridge2

Inspection & Ownership

Last InspectionJuly 2023
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number000000000002397

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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