Structure B162154VUMBTNBI · Suffolk County, MA

HWY Bnningtn ST over Tr Blue Line

Carries HWY Bnningtn ST over Tr Blue Line, Over Blue Line.

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 FT151 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 6/9Substructure 5/9 · sets the rating

151 ft end to end: 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.

Built1961rebuilt 2010
Length151.2 ft46.1 m
Daily traffic17,300counted 2012
Last inspectedJanuary 2023every 24 months

Location

StateMassachusetts
CountySuffolk
LocationOver Blue Line
CarriesHWY Bnningtn ST
CrossesTr Blue Line
Coordinates42.38843, -71.00023

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length151.2 ft (46.1 m)
Max Span95.1 ft (29 m)
Deck Width80.1 ft (24.4 m)
Deck Area1124.8 sq m
Main Spans1
Year Built1961 (reconstructed 2010)

Traffic

Avg Daily Traffic17,300 (2012)
Truck Traffic6%
Lanes On Bridge4

Inspection & Ownership

Last InspectionJanuary 2023
Inspection FrequencyEvery 24 months
OwnerOther State Agencies
Historical SignificanceHistorical significance is not determined
Scour CriticalNot applicable
Structure NumberB162154VUMBTNBI

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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