US Bridges

US 17 Alt over Spooler Swamp

Fair

Dorchester County, South Carolina · 13.8MI SW Summerville · Structure no. 000000000000408

Built
1930
95 years old, rebuilt 1971
Condition
Fair
inspected May 2024
Type
Slab
Concrete Continuous
Length
90 ft
9 main spans
Daily traffic
11,600
2023 count
Owner
State
State Highway Agency

About this bridge

US 17 Alt over Spooler Swamp is a concrete continuous slab carrying US 17 Alt over Spooler Swamp in Dorchester County, South Carolina. It was built in 1930 and reconstructed in 1971, so it is 95 years old, older than the South Carolina average of 48 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 11,600 vehicles a day, roughly 10% of them trucks, projected to reach 18,444 by 2043. The structure is 90 ft (27.4 m) long and 47 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesUS 17 Alt
CrossesSpooler Swamp
Location13.8MI SW Summerville
RouteU.S. Route 17
CountyDorchester County
StateSouth Carolina
Coordinates32.92797, -80.38222
Functional classRural Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44.6 US tons
Inventory rating26.8 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans9
Design loadH 10
Structure length90 ft (27.4 m)
Longest span10 ft (3 m)
Deck width47 ft (14.3 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,600 (2023)
Projected traffic18,444 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 17 Alt over Spooler Swamp built?

It was built in 1930, making it 95 years old in 2025. It was reconstructed in 1971.

What condition is US 17 Alt over Spooler Swamp in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in May 2024.

How much traffic does US 17 Alt over Spooler Swamp carry?

About 11,600 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is US 17 Alt over Spooler Swamp?

The structure is 90 ft (27.4 m) long with a longest span of 10 ft (3 m) and a deck 47 ft wide.

Who owns US 17 Alt over Spooler Swamp?

It is owned by the State Highway Agency.