US Bridges

HWY 240 over South Slough

FairPosted for load

Coos County, Oregon · Charleston · Structure no. 01940G240 00839

Built
1991
34 years old
Condition
Fair
inspected August 2023
Type
Movable - Bascule
Steel
Length
1,192 ft
1 main span
Daily traffic
5,624
2022 count
Owner
State
State Highway Agency

About this bridge

HWY 240 over South Slough is a steel movable - bascule carrying HWY 240 over South Slough in Coos County, Oregon. It was built in 1991, so it is 34 years old, younger than the Oregon average of 49.9 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. Its operating status is: posted for other load-capacity restriction.

It carries about 5,624 vehicles a day, roughly 3% of them trucks, projected to reach 5,700 by 2042. The structure is 1,192 ft (363.4 m) long and 48 ft wide. If it were closed, the detour would be 5.6 mi (9 km).

Location

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CarriesHWY 240
CrossesSouth Slough
LocationCharleston
RouteState Highway 540
CountyCoos County
StateOregon
Coordinates43.33892, -124.32123
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusPosted for other load-capacity restriction
ScourFoundations stable; action required to protect exposed foundations
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 adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating27.9 US tons
Inventory rating21.4 US tons

Structure

Structure typeMovable - Bascule
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+11 approach)
Design loadHS 25 or greater
Structure length1,192 ft (363.4 m)
Longest span126 ft (38.4 m)
Deck width48 ft (14.7 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,624 (2022)
Projected traffic5,700 by 2042
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed5.6 mi (9 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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was HWY 240 over South Slough built?

It was built in 1991, making it 34 years old in 2025.

What condition is HWY 240 over South Slough 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 August 2023.

How much traffic does HWY 240 over South Slough carry?

About 5,624 vehicles per day (2022 count), of which roughly 3% are trucks.

How long is HWY 240 over South Slough?

The structure is 1,192 ft (363.4 m) long with a longest span of 126 ft (38.4 m) and a deck 48 ft wide.

Who owns HWY 240 over South Slough?

It is owned by the State Highway Agency.