Structure 88277000000000 · Thurston County, WA

Old HWY 99 over Prairie Creek

Carries Old HWY 99 over Prairie Creek, 1. S Jct I-5.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 8 of 9.

How ratings work
Decksets the rating8/9 · Very Good
Superstructuresets the rating8/9 · Very Good
Substructuresets the rating8/9 · Very Good
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT63 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 8/9Substructure 8/9

63 ft end to end. Lengths and the car on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a slab bridge.

Built201016 years old
Length63.0 ft19.2 m
Daily traffic11,240counted 2021
Last inspectedJune 2023every 24 months

Location

StateWashington
CountyThurston
Location1. S Jct I-5
CarriesOld HWY 99
CrossesPrairie Creek
Coordinates46.79662, -123.01201

Physical Characteristics

MaterialPrestressed Concrete
DesignSlab
Total Length63.0 ft (19.2 m)
Max Span60.0 ft (18.3 m)
Deck Width79.1 ft (24.1 m)
Deck Area462.7 sq m
Main Spans1
Year Built2010

Traffic

Avg Daily Traffic11,240 (2021)
Truck Traffic20%
Lanes On Bridge3

Inspection & Ownership

Last InspectionJune 2023
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number088277000000000

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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