Structure 3780 · Ingham County, MI

I-496 EB over Forest RD

Carries I-496 EB over Forest RD, In Lansing (forest Rd).

Overall conditionPoor

Set by its lowest-rated component: Substructure at 4 of 9.

How ratings work
Deck7/9 · Good
Superstructure5/9 · Fair
Substructuresets the rating4/9 · Poor
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT108 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 5/9Substructure 4/9 · sets the rating

108 ft end to end, longest span 40 ft. Lengths and the car 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 multi-beam bridge.

Built196363 years old
Length107.6 ft32.8 m
Daily traffic29,013counted 2007
Last inspectedOctober 2023every 24 months

Location

StateMichigan
CountyIngham
LocationIn Lansing (forest Rd)
CarriesI-496 EB
CrossesForest RD
Coordinates42.70461, -84.50561

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length107.6 ft (32.8 m)
Max Span40.4 ft (12.3 m)
Deck Width42.7 ft (13 m)
Deck Area426.4 sq m
Main Spans3
Year Built1963

Traffic

Avg Daily Traffic29,013 (2007)
Truck Traffic7%
Lanes On Bridge2
Lanes Under Bridge2

Inspection & Ownership

Last InspectionOctober 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number000000000003780

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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