Structure 11030 · Washtenaw County, MI

Maple Road over Huron River

Carries Maple Road over Huron River, Ann Arbor Twp Sec 7.

Overall conditionFair

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

How ratings work
Deck6/9 · Satisfactory
Superstructuresets the rating5/9 · Fair
Substructure6/9 · Satisfactory
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT150 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 5/9 · sets the ratingSubstructure 6/9

150 ft end to end: about 2 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 truss.

Built1876rebuilt 2003
Length149.9 ft45.7 m
Daily traffic1,963counted 2004
Last inspectedMay 2024every 12 months

Location

StateMichigan
CountyWashtenaw
LocationAnn Arbor Twp Sec 7
CarriesMaple Road
CrossesHuron River
Coordinates42.31693, -83.77811

Physical Characteristics

MaterialSteel
DesignTruss - Thru
Total Length149.9 ft (45.7 m)
Max Span119.8 ft (36.5 m)
Deck Width16.1 ft (4.9 m)
Deck Area223.9 sq m
Main Spans1
Year Built1876 (reconstructed 2003)

Traffic

Avg Daily Traffic1,963 (2004)
Truck Traffic2%
Lanes On Bridge1

Inspection & Ownership

Last InspectionMay 2024
Inspection FrequencyEvery 12 months
OwnerCounty Highway Agency
Historical SignificanceBridge is on the National Register of Historic Places
Scour Critical3 — Scour critical
Structure Number000000000011030

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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