Structure 7172 · Monroe County, MI

I-75 over Cn Gtw & Ns Rrs

Carries I-75 over Cn Gtw & Ns Rrs, In Monroe.

Overall conditionFair

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

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

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT170 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 5/9 · sets the ratingSubstructure 5/9 · sets the rating

170 ft end to end, longest span 43 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 multi-beam bridge.

Built1954rebuilt 1989
Length169.9 ft51.8 m
Daily traffic63,766counted 2007
Last inspectedAugust 2023every 24 months

Location

StateMichigan
CountyMonroe
LocationIn Monroe
CarriesI-75
CrossesCn Gtw & Ns Rrs
Coordinates41.89904, -83.37400

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length169.9 ft (51.8 m)
Max Span43.0 ft (13.1 m)
Deck Width116.1 ft (35.4 m)
Deck Area1833.7 sq m
Main Spans4
Year Built1954 (reconstructed 1989)

Traffic

Avg Daily Traffic63,766 (2007)
Truck Traffic23%
Lanes On Bridge7
Lanes Under Bridge2

Inspection & Ownership

Last InspectionAugust 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number000000000007172

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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