US Bridges

SR 20 over Bonaparte CR

Good

Okanogan County, Washington · 4.6 E JCT US 97 · Structure no. 0015877A0000000

Built
2000
25 years old
Condition
Good
inspected August 2021
Type
Slab
Prestressed Concrete
Length
67 ft
1 main span
Daily traffic
1,755
2023 count
Owner
State
State Highway Agency

About this bridge

SR 20 over Bonaparte CR is a prestressed concrete slab carrying SR 20 over Bonaparte CR in Okanogan 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 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 1,755 vehicles a day, roughly 11% of them trucks, projected to reach 2,004 by 2039. The structure is 67 ft (20.4 m) long and 36 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesSR 20
CrossesBonaparte CR
Location4.6 E JCT US 97
RouteState Highway 20
CountyOkanogan County
StateWashington
Coordinates48.67217, -119.35794
Functional classRural Minor Arterial

Condition and inspection

Good

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating74 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHS 25 or greater
Structure length67 ft (20.4 m)
Longest span67 ft (20.4 m)
Deck width36 ft (11 m)
Roadway width33 ft (10.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,755 (2023)
Projected traffic2,004 by 2039
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$1.1 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 20 over Bonaparte CR built?

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

What condition is SR 20 over Bonaparte CR 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 2021.

How much traffic does SR 20 over Bonaparte CR carry?

About 1,755 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is SR 20 over Bonaparte CR?

The structure is 67 ft (20.4 m) long with a longest span of 67 ft (20.4 m) and a deck 36 ft wide.

Who owns SR 20 over Bonaparte CR?

It is owned by the State Highway Agency.