Structure 100000150120010 · Montgomery County, MD

Md 355 SB over Is 495 Il

Carries Md 355 SB over Is 495 Il, 1.31 Miles S Of Md 547.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructure6/9 · Satisfactory
Substructuresets the rating5/9 · Fair
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT294 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9Substructure 5/9 · sets the rating

294 ft end to end, longest span 138 ft: about 4 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.

Built1959rebuilt 1997
Length294.0 ft89.6 m
Daily traffic55,020counted 2009
Last inspectedOctober 2023every 24 months

Location

StateMaryland
CountyMontgomery
Location1.31 Miles S Of Md 547
CarriesMd 355 SB
CrossesIs 495 Il
Coordinates39.01739, -77.10206

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length294.0 ft (89.6 m)
Max Span138.1 ft (42.1 m)
Deck Width53.8 ft (16.4 m)
Deck Area1469.4 sq m
Main Spans3
Year Built1959 (reconstructed 1997)

Traffic

Avg Daily Traffic55,020 (2009)
Truck Traffic8%
Lanes On Bridge3
Lanes Under Bridge4

Inspection & Ownership

Last InspectionOctober 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number100000150120010

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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