Structure 35 · District of Columbia County, DC

M Street N.w. over Parkway & Rock Creek

Carries M Street N.w. over Parkway & Rock Creek, M St. Over Parkway N.w..

Overall conditionGood

Set by its lowest-rated component: Deck and Substructure at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructure8/9 · Very Good
Substructuresets the rating7/9 · Good
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT232 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9 · sets the ratingSuperstructure 8/9Substructure 7/9 · sets the rating

232 ft end to end, longest span 78 ft: about 3 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 multi-beam bridge.

Built1928rebuilt 1999
Length232.0 ft70.7 m
Daily traffic16,000counted 2018
Last inspectedAugust 2024every 24 months

Location

StateDistrict of Columbia
CountyDistrict of Columbia
LocationM St. Over Parkway N.w.
CarriesM Street N.w.
CrossesParkway & Rock Creek
Coordinates38.90526, -77.05586

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length232.0 ft (70.7 m)
Max Span78.1 ft (23.8 m)
Deck Width59.1 ft (18 m)
Deck Area1272.6 sq m
Main Spans3
Year Built1928 (reconstructed 1999)

Traffic

Avg Daily Traffic16,000 (2018)
Truck Traffic1%
Lanes On Bridge3
Lanes Under Bridge4

Inspection & Ownership

Last InspectionAugust 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is possibly eligible (requires evaluation)
Scour Critical5 — Stable for scour
Structure Number0035

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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