US Bridges

I-705 over Chehalis Western RR

Good

Pierce County, Washington · JCT I-5 & SR 7 · Structure no. 0012992A0000000

Built
1988
37 years old
Condition
Good
inspected August 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
1,451 ft
11 main spans
Daily traffic
15,025
2023 count
Owner
State
State Highway Agency

About this bridge

I-705 over Chehalis Western RR is a prestressed concrete continuous box beam or girders - multiple carrying I-705 over Chehalis Western RR in Pierce County, Washington. It was built in 1988, so it is 37 years old, younger than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 15,025 vehicles a day, roughly 4% of them trucks, projected to reach 21,675 by 2039. The structure is 1,451 ft (442.3 m) long and 40 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-705
CrossesChehalis Western RR
LocationJCT I-5 & SR 7
RouteInterstate 705
CountyPierce County
StateWashington
Coordinates47.235, -122.43167
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating79 US tons
Inventory rating47 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans11
Design loadHS 20 + Mod
Structure length1,451 ft (442.3 m)
Longest span140 ft (42.7 m)
Deck width40 ft (12.2 m)
Roadway width31 ft (9.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15,025 (2023)
Projected traffic21,675 by 2039
Trucks4%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and railroad
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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$37.2 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-705 over Chehalis Western RR built?

It was built in 1988, making it 37 years old in 2025.

What condition is I-705 over Chehalis Western RR in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in August 2023.

How much traffic does I-705 over Chehalis Western RR carry?

About 15,025 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is I-705 over Chehalis Western RR?

The structure is 1,451 ft (442.3 m) long with a longest span of 140 ft (42.7 m) and a deck 40 ft wide.

Who owns I-705 over Chehalis Western RR?

It is owned by the State Highway Agency.