US Bridges

I 93 /US1/ST3 over Water Neponset River

Fair

Suffolk County, Massachusetts · .8 KM S of JCT SR 3A · Structure no. B162503D1DOTNBI

Built
1954
71 years old, rebuilt 1984
Condition
Fair
inspected July 2023
Type
Girder and Floorbeam System
Steel Continuous
Length
478 ft
2 main spans
Daily traffic
169,936
2023 count
Owner
State
State Highway Agency

About this bridge

I 93 /US1/ST3 over Water Neponset River is a steel continuous girder and floorbeam system carrying I 93 /US1/ST3 over Water Neponset River in Suffolk County, Massachusetts. It was built in 1954 and reconstructed in 1984, so it is 71 years old, older 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 5 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 169,936 vehicles a day, roughly 7% of them trucks, projected to reach 293,750 by 2032. The structure is 478 ft (145.7 m) long and 118 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesI 93 /US1/ST3
CrossesWater Neponset River
Location.8 KM S of JCT SR 3A
RouteInterstate 93
CountySuffolk County
StateMassachusetts
Coordinates42.27778, -71.0484
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating61.8 US tons
Inventory rating37 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2 (+4 approach)
Design loadHS 20 + Mod
Structure length478 ft (145.7 m)
Longest span145 ft (44.2 m)
Deck width118 ft (36 m)
Roadway width110 ft (33.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic169,936 (2023)
Projected traffic293,750 by 2032
Trucks7%
Lanes on structure8
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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$51.2 million (2025 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was I 93 /US1/ST3 over Water Neponset River built?

It was built in 1954, making it 71 years old in 2025. It was reconstructed in 1984.

What condition is I 93 /US1/ST3 over Water Neponset River 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 July 2023.

How much traffic does I 93 /US1/ST3 over Water Neponset River carry?

About 169,936 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is I 93 /US1/ST3 over Water Neponset River?

The structure is 478 ft (145.7 m) long with a longest span of 145 ft (44.2 m) and a deck 118 ft wide.

Who owns I 93 /US1/ST3 over Water Neponset River?

It is owned by the State Highway Agency.