US Bridges

SR 105 over South Bay

Fair

Grays Harbor County, Washington · 1.9 N JCT SR 105 SP · Structure no. 0004869A0000000

Built
1955
70 years old
Condition
Fair
inspected April 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
1,309 ft
12 main spans
Daily traffic
5,550
2023 count
Owner
State
State Highway Agency

About this bridge

SR 105 over South Bay is a concrete continuous box beam or girders - multiple carrying SR 105 over South Bay in Grays Harbor County, Washington. It was built in 1955, so it is 70 years old, older than the Washington average of 49.8 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 5,550 vehicles a day, roughly 5% of them trucks, projected to reach 6,508 by 2039. The structure is 1,309 ft (399 m) long and 31 ft wide. If it were closed, the detour would be 70.8 mi (114 km).

Location

Open in Google Maps
CarriesSR 105
CrossesSouth Bay
Location1.9 N JCT SR 105 SP
RouteState Highway 105
CountyGrays Harbor County
StateWashington
Coordinates46.86175, -124.07106
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.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating22.5 US tons
Inventory rating17.5 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans12
Design loadH 15
Structure length1,309 ft (399 m)
Longest span165 ft (50.3 m)
Deck width31 ft (9.4 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,550 (2023)
Projected traffic6,508 by 2039
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed70.8 mi (114 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$24.9 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 105 over South Bay built?

It was built in 1955, making it 70 years old in 2025.

What condition is SR 105 over South Bay 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 April 2024.

How much traffic does SR 105 over South Bay carry?

About 5,550 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is SR 105 over South Bay?

The structure is 1,309 ft (399 m) long with a longest span of 165 ft (50.3 m) and a deck 31 ft wide.

Who owns SR 105 over South Bay?

It is owned by the State Highway Agency.