Structure 1570 · Chippewa County, MI

I-75 Bs (ashmun) over Power Canal

Carries I-75 Bs (ashmun) over Power Canal, In Sault Ste Marie.

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
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT257 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 5/9 · sets the ratingSubstructure 5/9 · sets the rating

257 ft end to end: about 4 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 through arch.

Built1934rebuilt 1998
Length256.9 ft78.3 m
Daily traffic10,180counted 2007
Last inspectedAugust 2024every 24 months

Location

StateMichigan
CountyChippewa
LocationIn Sault Ste Marie
CarriesI-75 Bs (ashmun)
CrossesPower Canal
Coordinates46.49544, -84.34930

Physical Characteristics

MaterialSteel
DesignArch - Thru
Total Length256.9 ft (78.3 m)
Max Span256.9 ft (78.3 m)
Deck Width62.0 ft (18.9 m)
Deck Area1479.9 sq m
Main Spans1
Year Built1934 (reconstructed 1998)

Traffic

Avg Daily Traffic10,180 (2007)
Truck Traffic3%
Lanes On Bridge3

Inspection & Ownership

Last InspectionAugust 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is on the National Register of Historic Places
Scour Critical8 — Stable, low risk
Structure Number000000000001570

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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