Structure 17176 001C29721 · Multnomah County, OR

Hwy91c To Hwy1nb over SW Terwilliger Blvd.

Carries Hwy91c To Hwy1nb over SW Terwilliger Blvd., 1.7 M S Of Ross Isl. Br..

Overall conditionFair

Set by its lowest-rated component: Deck at 5 of 9.

How ratings work
Decksets the rating5/9 · Fair
Superstructure6/9 · Satisfactory
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT370 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 6/9Substructure 7/9

370 ft end to end, longest span 130 ft: about 5 semi-trucks nose to tail. Lengths and the semi-truck 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 box-beam bridge.

Built199333 years old
Length370.1 ft112.8 m
Daily traffic12,141counted 2022
Last inspectedJanuary 2024every 24 months

Location

StateOregon
CountyMultnomah
Location1.7 M S Of Ross Isl. Br.
CarriesHwy91c To Hwy1nb
CrossesSW Terwilliger Blvd.
Coordinates45.46990, -122.68654

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length370.1 ft (112.8 m)
Max Span129.9 ft (39.6 m)
Deck Width36.7 ft (11.2 m)
Deck Area1263.4 sq m
Main Spans4
Year Built1993

Traffic

Avg Daily Traffic12,141 (2022)
Truck Traffic4%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJanuary 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number17176 001C29721

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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