Structure 1678 · Chippewa County, MI

Johnston St. over Power Canal

Carries Johnston St. over Power Canal, In Sault Ste Marie.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructuresets the rating5/9 · Fair
Substructure7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT284 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 5/9 · sets the ratingSubstructure 7/9

284 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 multi-beam bridge.

Built197947 years old
Length283.8 ft86.5 m
Daily traffic3,720counted 1997
Last inspectedJune 2023every 24 months

Location

StateMichigan
CountyChippewa
LocationIn Sault Ste Marie
CarriesJohnston St.
CrossesPower Canal
Coordinates46.49333, -84.34091

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length283.8 ft (86.5 m)
Max Span276.9 ft (84.4 m)
Deck Width42.3 ft (12.9 m)
Deck Area1115.8 sq m
Main Spans1
Year Built1979

Traffic

Avg Daily Traffic3,720 (1997)
Truck Traffic53%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJune 2023
Inspection FrequencyEvery 24 months
OwnerCity/Municipal Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number000000000001678

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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