US Bridges

Sc 171 over Wappoo Creek

Fair

Charleston County, South Carolina · 1 MI S of US 17 James Isl · Structure no. 000000000002303

Built
1956
69 years old
Condition
Fair
inspected October 2024
Type
Movable - Bascule
Steel
Length
762 ft
1 main span
Daily traffic
45,400
2023 count
Owner
State
State Highway Agency

About this bridge

Sc 171 over Wappoo Creek is a steel movable - bascule carrying Sc 171 over Wappoo Creek in Charleston County, South Carolina. It was built in 1956, so it is 69 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 5 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 45,400 vehicles a day, roughly 3% of them trucks, projected to reach 55,388 by 2043. The structure is 762 ft (232.2 m) long and 57 ft wide. If it were closed, the detour would be 18 mi (29 km).

Location

Open in Google Maps
CarriesSc 171
CrossesWappoo Creek
Location1 MI S of US 17 James Isl
RouteState Highway 171
CountyCharleston County
StateSouth Carolina
Coordinates32.76637, -79.97409
Functional classUrban 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating35.7 US tons
Inventory rating21.4 US tons

Structure

Structure typeMovable - Bascule
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+10 approach)
Design loadHS 15
Structure length762 ft (232.2 m)
Longest span153 ft (46.5 m)
Deck width57 ft (17.5 m)
Roadway width50 ft (15.2 m)
Vertical clearance over deck20 ft (6 m)

Traffic and service

Average daily traffic45,400 (2023)
Projected traffic55,388 by 2043
Trucks3%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed18 mi (29 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$5.1 million (2024 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was Sc 171 over Wappoo Creek built?

It was built in 1956, making it 69 years old in 2025.

What condition is Sc 171 over Wappoo Creek 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 October 2024.

How much traffic does Sc 171 over Wappoo Creek carry?

About 45,400 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is Sc 171 over Wappoo Creek?

The structure is 762 ft (232.2 m) long with a longest span of 153 ft (46.5 m) and a deck 57 ft wide.

Who owns Sc 171 over Wappoo Creek?

It is owned by the State Highway Agency.