US Bridges

US 17 Alt over Ashley River

Poor

Dorchester County, South Carolina · 6 MI S of Summerville · Structure no. 000000000005928

Built
1971
54 years old
Condition
Poor
inspected May 2024
Type
Tee Beam
Concrete
Length
210 ft
7 main spans
Daily traffic
19,800
2023 count
Owner
State
State Highway Agency

About this bridge

US 17 Alt over Ashley River is a concrete tee beam carrying US 17 Alt over Ashley River in Dorchester County, South Carolina. It was built in 1971, so it is 54 years old, older than the South Carolina average of 48 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 19,800 vehicles a day, roughly 10% of them trucks, projected to reach 24,156 by 2043. The structure is 210 ft (64 m) long and 48 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

Open in Google Maps
CarriesUS 17 Alt
CrossesAshley River
Location6 MI S of Summerville
RouteU.S. Route 17
CountyDorchester County
StateSouth Carolina
Coordinates32.96865, -80.25293
Functional classRural Minor Arterial

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 12 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating45.3 US tons
Inventory rating35.1 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans7
Design loadHS 20
Structure length210 ft (64 m)
Longest span30 ft (9.1 m)
Deck width48 ft (14.5 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic19,800 (2023)
Projected traffic24,156 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.7 mi (14 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 Ashley River built?

It was built in 1971, making it 54 years old in 2025.

What condition is US 17 Alt over Ashley River in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in May 2024.

How much traffic does US 17 Alt over Ashley River carry?

About 19,800 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is US 17 Alt over Ashley River?

The structure is 210 ft (64 m) long with a longest span of 30 ft (9.1 m) and a deck 48 ft wide.

Who owns US 17 Alt over Ashley River?

It is owned by the State Highway Agency.