Structure 8430 · Ogemaw County, MI

I-75 SB over M-30

Carries I-75 SB over M-30, 2.0 Mi S Of West Branch.

Overall conditionFair

Set by its lowest-rated component: Substructure at 5 of 9.

How ratings work
Deck6/9 · Satisfactory
Superstructure6/9 · Satisfactory
Substructuresets the rating5/9 · Fair
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT187 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 6/9Substructure 5/9 · sets the rating

187 ft end to end, longest span 95 ft: about 3 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 multi-beam bridge.

Built197254 years old
Length187.0 ft57 m
Daily traffic5,956counted 2020
Last inspectedOctober 2023every 24 months

Location

StateMichigan
CountyOgemaw
Location2.0 Mi S Of West Branch
CarriesI-75 SB
CrossesM-30
Coordinates44.25506, -84.24718

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length187.0 ft (57 m)
Max Span94.8 ft (28.9 m)
Deck Width44.3 ft (13.5 m)
Deck Area769.5 sq m
Main Spans3
Year Built1972

Traffic

Avg Daily Traffic5,956 (2020)
Truck Traffic11%
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 Number000000000008430

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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