Structure 1538 · Cheboygan County, MI

Black River Road over Black River

Carries Black River Road over Black River, Between Sec 7&8 T36nr1e.

Overall conditionFair

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

How ratings work
Deck8/9 · Very Good
Superstructure8/9 · Very Good
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT240 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 8/9Substructure 6/9 · sets the rating

240 ft end to end, longest span 48 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 box-beam bridge.

Built1975rebuilt 2020
Length240.2 ft73.2 m
Daily traffic1,100counted 2019
Last inspectedJuly 2024every 24 months

Location

StateMichigan
CountyCheboygan
LocationBetween Sec 7&8 T36nr1e
CarriesBlack River Road
CrossesBlack River
Coordinates45.51709, -84.35100

Physical Characteristics

MaterialPrestressed Concrete
DesignBox Beam - Multiple
Total Length240.2 ft (73.2 m)
Max Span47.9 ft (14.6 m)
Deck Width40.7 ft (12.4 m)
Deck Area907.7 sq m
Main Spans5
Year Built1975 (reconstructed 2020)

Traffic

Avg Daily Traffic1,100 (2019)
Truck Traffic20%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJuly 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number000000000001538

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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