Structure 31869 · St. Louis County, MO

Mo 231 S over Is 255

Carries Mo 231 S over Is 255, S 1 T 43 N R 6 E.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure7/9 · Good
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT240 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 7/9

240 ft end to end, longest span 120 ft: about 3 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.

Built200719 years old
Length240.2 ft73.2 m
Daily traffic41,695counted 2024
Last inspectedJuly 2024every 24 months

Location

StateMissouri
CountySt. Louis
LocationS 1 T 43 N R 6 E
CarriesMo 231 S
CrossesIs 255
Coordinates38.49481, -90.30199

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length240.2 ft (73.2 m)
Max Span120.1 ft (36.6 m)
Deck Width102.7 ft (31.3 m)
Deck Area2291.2 sq m
Main Spans2
Year Built2007

Traffic

Avg Daily Traffic41,695 (2024)
Truck Traffic4%
Lanes On Bridge7
Lanes Under Bridge8

Inspection & Ownership

Last InspectionJuly 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceHistorical significance is not determined
Scour CriticalNot applicable
Structure Number31869

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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