Structure 1401 · Calhoun County, MI

N Twentieth ST over Kalamazoo River

Carries N Twentieth ST over Kalamazoo River, 0.2 Mi S Of Michigan AVE.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructuresets the rating6/9 · Satisfactory
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 FT335 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 6/9 · sets the rating

335 ft end to end, longest span 42 ft: about 5 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.

Built1963rebuilt 1985
Length335.0 ft102.1 m
Daily traffic6,500counted 2022
Last inspectedNovember 2023every 24 months

Location

StateMichigan
CountyCalhoun
Location0.2 Mi S Of Michigan AVE
CarriesN Twentieth ST
CrossesKalamazoo River
Coordinates42.33480, -85.21941

Physical Characteristics

MaterialPrestressed Concrete
DesignBox Beam - Multiple
Total Length335.0 ft (102.1 m)
Max Span42.0 ft (12.8 m)
Deck Width58.4 ft (17.8 m)
Deck Area1817.4 sq m
Main Spans8
Year Built1963 (reconstructed 1985)

Traffic

Avg Daily Traffic6,500 (2022)
Truck Traffic17%
Lanes On Bridge2

Inspection & Ownership

Last InspectionNovember 2023
Inspection FrequencyEvery 24 months
OwnerCity/Municipal Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure Number000000000001401

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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