Structure 9823 · Charleston County, SC

US 17 over Marsh

Carries US 17 over Marsh, Charleston City Limit.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructuresets the rating7/9 · Good
Substructuresets the rating7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT1,086 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

1,086 ft end to end, longest span 138 ft: about 3.0 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 multi-beam bridge.

Built200521 years old
Length1086.0 ft331 m
Daily traffic94,100counted 2023
Last inspectedMay 2023every 24 months

Location

StateSouth Carolina
CountyCharleston
LocationCharleston City Limit
CarriesUS 17
CrossesMarsh
Coordinates32.80486, -79.93616

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignStringer/Multi-beam
Total Length1086.0 ft (331 m)
Max Span138.1 ft (42.1 m)
Deck Width117.1 ft (35.7 m)
Deck Area11816.7 sq m
Main Spans8
Year Built2005

Traffic

Avg Daily Traffic94,100 (2023)
Truck Traffic3%
Lanes On Bridge8

Inspection & Ownership

Last InspectionMay 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure Number000000000009823

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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