Structure B16677BQ8MBTNBI · Suffolk County, MA

HWY So Sta Ib Rp over Rr Mbta

Carries HWY So Sta Ib Rp over Rr Mbta, South Station.

Overall conditionGood

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

How ratings work
Decksets the rating7/9 · Good
Superstructuresets the rating7/9 · Good
Substructuresets the rating7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT396 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

396 ft end to end, longest span 91 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.

Built199531 years old
Length396.0 ft120.7 m
Last inspectedOctober 2021every 24 months

Location

StateMassachusetts
CountySuffolk
LocationSouth Station
CarriesHWY So Sta Ib Rp
CrossesRr Mbta
Coordinates42.34893, -71.05625

Physical Characteristics

MaterialSteel
DesignBox Beam - Multiple
Total Length396.0 ft (120.7 m)
Max Span90.9 ft (27.7 m)
Deck Width24.9 ft (7.6 m)
Deck Area917.3 sq m
Main Spans6
Year Built1995

Traffic

Lanes On Bridge1

Inspection & Ownership

Last InspectionOctober 2021
Inspection FrequencyEvery 24 months
OwnerOther State Agencies
Historical SignificanceHistorical significance is not determined
Scour CriticalNot applicable
Structure NumberB16677BQ8MBTNBI

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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