Structure B163904F7DOTNBI · Suffolk County, MA

ST 3 A/morrsy Blv over Comb Neponset Ave&river

Carries ST 3 A/morrsy Blv over Comb Neponset Ave&river, .2 Mi E Of I 93.

Overall conditionFair

Set by its lowest-rated component: Superstructure at 6 of 9.

How ratings work
Deck7/9 · Good
Superstructuresets the rating6/9 · Satisfactory
Substructure7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT1,018 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 7/9

1,018 ft end to end, longest span 176 ft: about 2.8 football fields. 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.

Built1970rebuilt 2012
Length1018.0 ft310.3 m
Daily traffic76,500counted 2019
Last inspectedApril 2023every 24 months

Location

StateMassachusetts
CountySuffolk
Location.2 Mi E Of I 93
CarriesST 3 A/morrsy Blv
CrossesComb Neponset Ave&river
Coordinates42.28444, -71.03953

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length1018.0 ft (310.3 m)
Max Span175.9 ft (53.6 m)
Deck Width98.8 ft (30.1 m)
Deck Area9340.0 sq m
Main Spans9
Year Built1970 (reconstructed 2012)

Traffic

Avg Daily Traffic76,500 (2019)
Truck Traffic2%
Lanes On Bridge6
Lanes Under Bridge1

Inspection & Ownership

Last InspectionApril 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure NumberB163904F7DOTNBI

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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