US Bridges

Park Entrance over Twanoh Creek

FairPosted for load

Mason County, Washington · Twanoh State Park · Structure no. 086480000000000

Built
2000
25 years old
Condition
Fair
inspected February 2023
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
22 ft
1 main span
Daily traffic
125
2012 count
Owner
State
State Park, Forest, or Reservation Agency

About this bridge

Park Entrance over Twanoh Creek is a wood or timber stringer/multi-beam or girder carrying Park Entrance over Twanoh Creek in Mason County, Washington. It was built in 2000, so it is 25 years old, younger 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. Its operating status is: posted for load restriction.

It carries about 125 vehicles a day, projected to reach 161 by 2036. The structure is 22 ft (6.7 m) long and 22 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesPark Entrance
CrossesTwanoh Creek
LocationTwanoh State Park
RouteState Lands Road 81001
CountyMason County
StateWashington
Coordinates47.37763, -122.97336
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating19 US tons
Inventory rating15 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadUnknown
Structure length22 ft (6.7 m)
Longest span21 ft (6.4 m)
Deck width22 ft (6.7 m)
Roadway width21 ft (6.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic125 (2012)
Projected traffic161 by 2036
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Park, Forest, or Reservation Agency
Maintained byState Park, Forest, or Reservation Agency
Historic statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$240,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Park Entrance over Twanoh Creek built?

It was built in 2000, making it 25 years old in 2025.

What condition is Park Entrance over Twanoh 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 February 2023.

How much traffic does Park Entrance over Twanoh Creek carry?

About 125 vehicles per day (2012 count).

How long is Park Entrance over Twanoh Creek?

The structure is 22 ft (6.7 m) long with a longest span of 21 ft (6.4 m) and a deck 22 ft wide.

Who owns Park Entrance over Twanoh Creek?

It is owned by the State Park, Forest, or Reservation Agency.