Structure B161693HMDOT634 · Suffolk County, MA

HWY Fairmont AVE over Comb Walnut ST & Mbta

Carries HWY Fairmont AVE over Comb Walnut ST & Mbta, 1 Mi W Of Sr138/nep Pkw..

Overall conditionFair

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

How ratings work
Deck6/9 · Satisfactory
Superstructure6/9 · Satisfactory
Substructuresets the rating5/9 · Fair
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT174 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 6/9Substructure 5/9 · sets the rating

174 ft end to end, longest span 76 ft: about 2 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.

Built1908rebuilt 1984
Length173.9 ft53 m
Daily traffic14,483counted 2024
Last inspectedSeptember 2024every 24 months

Location

StateMassachusetts
CountySuffolk
Location1 Mi W Of Sr138/nep Pkw.
CarriesHWY Fairmont AVE
CrossesComb Walnut ST & Mbta
Coordinates42.25364, -71.11942

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length173.9 ft (53 m)
Max Span76.1 ft (23.2 m)
Deck Width52.8 ft (16.1 m)
Deck Area853.3 sq m
Main Spans3
Year Built1908 (reconstructed 1984)

Traffic

Avg Daily Traffic14,483 (2024)
Truck Traffic4%
Lanes On Bridge2
Lanes Under Bridge2

Inspection & Ownership

Last InspectionSeptember 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure NumberB161693HMDOT634

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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