Structure 8081 · Oakland County, MI

I-75 NB over Adams RD

Carries I-75 NB over Adams RD, In Troy (over Adams Rd).

Overall conditionGood

Set by its lowest-rated component: Substructure at 7 of 9.

How ratings work
Deck8/9 · Very Good
Superstructure8/9 · Very Good
Substructuresets the rating7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT153 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 8/9Substructure 7/9 · sets the rating

153 ft end to end, longest span 82 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.

Built20179 years old
Length153.2 ft46.7 m
Daily traffic53,391counted 2007
Last inspectedDecember 2023every 24 months

Location

StateMichigan
CountyOakland
LocationIn Troy (over Adams Rd)
CarriesI-75 NB
CrossesAdams RD
Coordinates42.60677, -83.20855

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length153.2 ft (46.7 m)
Max Span81.7 ft (24.9 m)
Deck Width82.3 ft (25.1 m)
Deck Area1172.2 sq m
Main Spans3
Year Built2017

Traffic

Avg Daily Traffic53,391 (2007)
Truck Traffic8%
Lanes On Bridge4
Lanes Under Bridge4

Inspection & Ownership

Last InspectionDecember 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number000000000008081

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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