Structure 7705 · Muskegon County, MI

Henry Street over Mona Lake

Carries Henry Street over Mona Lake, Norton Shores.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructuresets the rating6/9 · Satisfactory
Substructure7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT946 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 7/9

946 ft end to end, longest span 70 ft: about 2.6 football fields. 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.

Built198838 years old
Length946.2 ft288.4 m
Daily traffic25,000counted 2016
Last inspectedMay 2023every 24 months

Location

StateMichigan
CountyMuskegon
LocationNorton Shores
CarriesHenry Street
CrossesMona Lake
Coordinates43.17942, -86.26369

Physical Characteristics

MaterialPrestressed Concrete
DesignBox Beam - Multiple
Total Length946.2 ft (288.4 m)
Max Span69.9 ft (21.3 m)
Deck Width63.3 ft (19.3 m)
Deck Area5566.1 sq m
Main Spans19
Year Built1988

Traffic

Avg Daily Traffic25,000 (2016)
Truck Traffic5%
Lanes On Bridge2

Inspection & Ownership

Last InspectionMay 2023
Inspection FrequencyEvery 24 months
OwnerCity/Municipal Highway Agency
Historical SignificanceBridge is on the National Register of Historic Places
Scour Critical8 — Stable, low risk
Structure Number000000000007705

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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