Structure 7425 · Beaufort County, SC

US 21 SB over Beaufort River

Carries US 21 SB over Beaufort River, Southeast Of Beaufort.

Overall conditionPoor

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

How ratings work
Deck6/9 · Satisfactory
Superstructure6/9 · Satisfactory
Substructuresets the rating4/9 · Poor
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
4,210 FT OVERALL500 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 6/9Substructure 4/9 · sets the rating

4,210 ft end to end, longest span 170 ft: about 12 football fields. Lengths are drawn to scale; at this length a semi-truck would be a speck. 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.

Built197947 years old
Length4210.0 ft1283.2 m
Daily traffic14,400counted 2023
Last inspectedSeptember 2024every 12 months

Location

StateSouth Carolina
CountyBeaufort
LocationSoutheast Of Beaufort
CarriesUS 21 SB
CrossesBeaufort River
Coordinates32.39392, -80.67539

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length4210.0 ft (1283.2 m)
Max Span169.9 ft (51.8 m)
Deck Width39.4 ft (12 m)
Deck Area15398.4 sq m
Main Spans15
Year Built1979

Traffic

Avg Daily Traffic14,400 (2023)
Truck Traffic6%
Lanes On Bridge2

Inspection & Ownership

Last InspectionSeptember 2024
Inspection FrequencyEvery 12 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number000000000007425

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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