US Bridges

I 93 NB over I 93 SB

Fair

Suffolk County, Massachusetts · I93/US1 Interchange · Structure no. B16600900DOTNBI

Built
2003
22 years old
Condition
Fair
inspected January 2022
Type
Segmental Box Girder
Prestressed Concrete Continuous
Length
547 ft
4 main spans
Daily traffic
70,395
2020 count
Owner
State
State Highway Agency

About this bridge

I 93 NB over I 93 SB is a prestressed concrete continuous segmental box girder carrying I 93 NB over I 93 SB in Suffolk County, Massachusetts. It was built in 2003, so it is 22 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 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 70,395 vehicles a day, roughly 6% of them trucks, projected to reach 92,688 by 2031. The structure is 547 ft (166.7 m) long and 54 ft wide. If it were closed, the detour would be 2.5 mi (4 km).

Location

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CarriesI 93 NB
CrossesI 93 SB
LocationI93/US1 Interchange
RouteInterstate 93
CountySuffolk County
StateMassachusetts
Coordinates42.37231, -71.0678
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.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJanuary 2022
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
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
Approach roadway alignment8: Equal to present desirable criteria
Operating rating87.7 US tons
Inventory rating52.4 US tons

Structure

Structure typeSegmental Box Girder
MaterialPrestressed Concrete Continuous
DeckOther
Main spans4
Design loadHS 25 or greater
Structure length547 ft (166.7 m)
Longest span143 ft (43.6 m)
Deck width54 ft (16.5 m)
Roadway width50 ft (15.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic70,395 (2020)
Projected traffic92,688 by 2031
Trucks6%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed2.5 mi (4 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 statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$26.8 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 93 NB over I 93 SB built?

It was built in 2003, making it 22 years old in 2025.

What condition is I 93 NB over I 93 SB 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 January 2022.

How much traffic does I 93 NB over I 93 SB carry?

About 70,395 vehicles per day (2020 count), of which roughly 6% are trucks.

How long is I 93 NB over I 93 SB?

The structure is 547 ft (166.7 m) long with a longest span of 143 ft (43.6 m) and a deck 54 ft wide.

Who owns I 93 NB over I 93 SB?

It is owned by the State Highway Agency.