US Bridges

I-90 over SR 21

Poor

Adams County, Washington · 15.5 E Grant CO · Structure no. 0009185C0000000

Built
1972
53 years old
Condition
Poor
inspected July 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
200 ft
3 main spans
Daily traffic
5,897
2023 count
Owner
State
State Highway Agency

About this bridge

I-90 over SR 21 is a prestressed concrete continuous stringer/multi-beam or girder carrying I-90 over SR 21 in Adams County, Washington. It was built in 1972, so it is 53 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 5,897 vehicles a day, roughly 23% of them trucks, projected to reach 6,832 by 2039. The structure is 200 ft (61 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-90
CrossesSR 21
Location15.5 E Grant CO
RouteInterstate 90
CountyAdams County
StateWashington
Coordinates47.09683, -118.66806
Functional classRural Principal Arterial - Interstate

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating76.9 US tons
Inventory rating45 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length200 ft (61 m)
Longest span67 ft (20.4 m)
Deck width40 ft (12.3 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,897 (2023)
Projected traffic6,832 by 2039
Trucks23%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
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$4.1 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-90 over SR 21 built?

It was built in 1972, making it 53 years old in 2025.

What condition is I-90 over SR 21 in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in July 2024.

How much traffic does I-90 over SR 21 carry?

About 5,897 vehicles per day (2023 count), of which roughly 23% are trucks.

How long is I-90 over SR 21?

The structure is 200 ft (61 m) long with a longest span of 67 ft (20.4 m) and a deck 40 ft wide.

Who owns I-90 over SR 21?

It is owned by the State Highway Agency.