US Bridges

Sea Island Road over Dunbar Creek

Fair

Glynn County, Georgia · 2.4 MI N ST Simons Island · Structure no. 000000012700660

Built
1960
65 years old
Condition
Fair
inspected October 2024
Type
Channel Beam
Concrete
Length
325 ft
13 main spans
Daily traffic
15,100
2024 count
Owner
County
County Highway Agency

About this bridge

Sea Island Road over Dunbar Creek is a concrete channel beam carrying Sea Island Road over Dunbar Creek in Glynn County, Georgia. It was built in 1960, so it is 65 years old, older than the Georgia average of 47.5 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 15,100 vehicles a day, roughly 1% of them trucks, projected to reach 20,100 by 2031. The structure is 325 ft (99.1 m) long and 31 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesSea Island Road
CrossesDunbar Creek
Location2.4 MI N ST Simons Island
RouteCounty Highway 1550
CountyGlynn County
StateGeorgia
Coordinates31.18572, -81.38868
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating39.9 US tons
Inventory rating23.9 US tons

Structure

Structure typeChannel Beam
MaterialConcrete
DeckConcrete, precast panels
Main spans13
Design loadH 15
Structure length325 ft (99.1 m)
Longest span25 ft (7.6 m)
Deck width31 ft (9.6 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15,100 (2024)
Projected traffic20,100 by 2031
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$1.9 million
NavigationNo navigation control on waterway

Frequently asked questions

When was Sea Island Road over Dunbar Creek built?

It was built in 1960, making it 65 years old in 2025.

What condition is Sea Island Road over Dunbar 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 Sea Island Road over Dunbar Creek carry?

About 15,100 vehicles per day (2024 count), of which roughly 1% are trucks.

How long is Sea Island Road over Dunbar Creek?

The structure is 325 ft (99.1 m) long with a longest span of 25 ft (7.6 m) and a deck 31 ft wide.

Who owns Sea Island Road over Dunbar Creek?

It is owned by the County Highway Agency.