Structure 326 · Alpena County, MI

M-65 over Thunder Bay River

Carries M-65 over Thunder Bay River, 0.5 Mi S Of Long Rapids.

Overall conditionPoor

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

How ratings work
Decksets the rating4/9 · Poor
Superstructure5/9 · Fair
Substructure5/9 · Fair
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT201 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 4/9 · sets the ratingSuperstructure 5/9Substructure 5/9

201 ft end to end, longest span 37 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 tee-beam bridge.

Built195373 years old
Length201.4 ft61.4 m
Daily traffic1,861counted 2007
Last inspectedJuly 2024every 12 months

Location

StateMichigan
CountyAlpena
Location0.5 Mi S Of Long Rapids
CarriesM-65
CrossesThunder Bay River
Coordinates45.12080, -83.72233

Physical Characteristics

MaterialConcrete
DesignTee Beam
Total Length201.4 ft (61.4 m)
Max Span36.7 ft (11.2 m)
Deck Width33.5 ft (10.2 m)
Deck Area626.3 sq m
Main Spans5
Year Built1953

Traffic

Avg Daily Traffic1,861 (2007)
Truck Traffic8%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJuly 2024
Inspection FrequencyEvery 12 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical3 — Scour critical
Structure Number000000000000326

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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