Structure L150862JPDOTNBI · Middlesex County, MA

I 495 NB over Rr Pan Am

Carries I 495 NB over Rr Pan Am, 0.25 Mi S Of St-38.

Overall conditionPoor

Set by its lowest-rated component: Superstructure at 4 of 9.

How ratings work
Deck5/9 · Fair
Superstructuresets the rating4/9 · Poor
Substructure6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT176 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9Superstructure 4/9 · sets the ratingSubstructure 6/9

176 ft end to end, longest span 58 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.

Built196165 years old
Length175.9 ft53.6 m
Daily traffic64,233counted 2018
Last inspectedSeptember 2023every 12 months

Location

StateMassachusetts
CountyMiddlesex
Location0.25 Mi S Of St-38
CarriesI 495 NB
CrossesRr Pan Am
Coordinates42.62452, -71.27723

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length175.9 ft (53.6 m)
Max Span58.1 ft (17.7 m)
Deck Width57.1 ft (17.4 m)
Deck Area932.6 sq m
Main Spans3
Year Built1961

Traffic

Avg Daily Traffic64,233 (2018)
Truck Traffic6%
Lanes On Bridge3

Inspection & Ownership

Last InspectionSeptember 2023
Inspection FrequencyEvery 12 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure NumberL150862JPDOTNBI

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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