US Bridges

I 495 NB over ST 1 A/South ST

Fair

Norfolk County, Massachusetts · At ST 1A · Structure no. W460103RXDOTNBI

Built
1966
59 years old
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
92 ft
1 main span
Daily traffic
41,841
2022 count
Owner
State
State Highway Agency

About this bridge

I 495 NB over ST 1 A/South ST is a steel stringer/multi-beam or girder carrying I 495 NB over ST 1 A/South ST in Norfolk County, Massachusetts. It was built in 1966, so it is 59 years old, younger than the Massachusetts average of 63.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 41,841 vehicles a day, roughly 6% of them trucks, projected to reach 71,068 by 2032. The structure is 92 ft (28 m) long and 58 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI 495 NB
CrossesST 1 A/South ST
LocationAt ST 1A
RouteInterstate 495
CountyNorfolk County
StateMassachusetts
Coordinates42.04032, -71.34502
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating58.4 US tons
Inventory rating34.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length92 ft (28 m)
Longest span90 ft (27.4 m)
Deck width58 ft (17.7 m)
Roadway width52 ft (15.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic41,841 (2022)
Projected traffic71,068 by 2032
Trucks6%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$5 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 495 NB over ST 1 A/South ST built?

It was built in 1966, making it 59 years old in 2025.

What condition is I 495 NB over ST 1 A/South ST in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in November 2023.

How much traffic does I 495 NB over ST 1 A/South ST carry?

About 41,841 vehicles per day (2022 count), of which roughly 6% are trucks.

How long is I 495 NB over ST 1 A/South ST?

The structure is 92 ft (28 m) long with a longest span of 90 ft (27.4 m) and a deck 58 ft wide.

Who owns I 495 NB over ST 1 A/South ST?

It is owned by the State Highway Agency.