Structure 8422 · Charleston County, SC

I-526 WB over US 17

Carries I-526 WB over US 17, In Mt. Pleasant.

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
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT269 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 7/9

269 ft end to end, longest span 168 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.

Built199135 years old
Length269.0 ft82 m
Daily traffic20,750counted 2023
Last inspectedAugust 2024every 24 months

Location

StateSouth Carolina
CountyCharleston
LocationIn Mt. Pleasant
CarriesI-526 WB
CrossesUS 17
Coordinates32.81428, -79.84943

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length269.0 ft (82 m)
Max Span168.0 ft (51.2 m)
Deck Width54.8 ft (16.7 m)
Deck Area1369.4 sq m
Main Spans3
Year Built1991

Traffic

Avg Daily Traffic20,750 (2023)
Truck Traffic4%
Lanes On Bridge3
Lanes Under Bridge7

Inspection & Ownership

Last InspectionAugust 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceHistorical significance is not determined
Scour CriticalNot applicable
Structure Number000000000008422

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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