Structure 38460300000000 · Iroquois County, IL

Fas-330 Ch31 over Iroquois River

Carries Fas-330 Ch31 over Iroquois River, 1mi N Watseka On 31.

Overall conditionPoor

Set by its lowest-rated component: Substructure at 4 of 9.

How ratings work
Deck6/9 · Satisfactory
Superstructure7/9 · Good
Substructuresets the rating4/9 · Poor
Channelnot part of overall5/9 · Fair
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT255 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 7/9Substructure 4/9 · sets the rating

255 ft end to end, longest span 97 ft: 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.

Built196561 years old
Length254.9 ft77.7 m
Daily traffic1,200counted 2022
Last inspectedSeptember 2023every 24 months

Location

StateIllinois
CountyIroquois
Location1mi N Watseka On 31
CarriesFas-330 Ch31
CrossesIroquois River
Coordinates40.79349, -87.70564

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length254.9 ft (77.7 m)
Max Span97.1 ft (29.6 m)
Deck Width34.4 ft (10.5 m)
Deck Area815.9 sq m
Main Spans3
Year Built1965

Traffic

Avg Daily Traffic1,200 (2022)
Truck Traffic7%
Lanes On Bridge2

Inspection & Ownership

Last InspectionSeptember 2023
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure Number038460300000000

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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