Structure 56314800000000 · McHenry County, IL

Algonquin RD over Spring CR

Carries Algonquin RD over Spring CR, 0.1 Mi SW Plum Tree.

Overall conditionPoor

Set by its lowest-rated component: Deck and Superstructure at 3 of 9.

How ratings work
Decksets the rating3/9 · Serious
Superstructuresets the rating3/9 · Serious
Substructure8/9 · Very Good
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT53 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 3/9 · sets the ratingSuperstructure 3/9 · sets the ratingSubstructure 8/9

53 ft end to end. Lengths and the car 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.

Built198640 years old
Length53.1 ft16.2 m
Daily traffic3,200counted 2021
Last inspectedSeptember 2023every 24 months

Location

StateIllinois
CountyMcHenry
Location0.1 Mi SW Plum Tree
CarriesAlgonquin RD
CrossesSpring CR
Coordinates42.18768, -88.22911

Physical Characteristics

MaterialPrestressed Concrete
DesignBox Beam - Multiple
Total Length53.1 ft (16.2 m)
Max Span51.8 ft (15.8 m)
Deck Width32.2 ft (9.8 m)
Deck Area158.8 sq m
Main Spans1
Year Built1986

Traffic

Avg Daily Traffic3,200 (2021)
Truck Traffic3%
Lanes On Bridge2

Inspection & Ownership

Last InspectionSeptember 2023
Inspection FrequencyEvery 24 months
OwnerTown/Township Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number056314800000000

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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