Structure H12039C32DOTNBI · Essex County, MA

I 495 NB over Water Merrimack River

Carries I 495 NB over Water Merrimack River, .4 Mi S St110.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 8 of 9.

How ratings work
Decksets the rating8/9 · Very Good
Superstructuresets the rating8/9 · Very Good
Substructuresets the rating8/9 · Very Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT722 FT OVERALL100 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 8/9Substructure 8/9

722 ft end to end, longest span 278 ft: about 2.0 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.

Built20215 years old
Length721.8 ft220 m
Daily traffic60,941counted 2023
Last inspectedJuly 2024every 24 months

Location

StateMassachusetts
CountyEssex
Location.4 Mi S St110
CarriesI 495 NB
CrossesWater Merrimack River
Coordinates42.76851, -71.12023

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length721.8 ft (220 m)
Max Span277.9 ft (84.7 m)
Deck Width79.4 ft (24.2 m)
Deck Area5,324 sq m
Main Spans3
Year Built2021

Traffic

Avg Daily Traffic60,941 (2023)
Truck Traffic1%
Lanes On Bridge4

Inspection & Ownership

Last InspectionJuly 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceHistorical significance is not determined
Scour Critical8 — Stable, low risk
Structure NumberH12039C32DOTNBI

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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