US Bridges

I 93 SB B16-SB4 over Comb Cambrige&mbta/Bmrr

Fair

Suffolk County, Massachusetts · 1.2 MI N of JCT I93&US1 · Structure no. B162813EGDOTNBI

Built
1970
55 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
1,214 ft
11 main spans
Daily traffic
77,596
2022 count
Owner
State
State Highway Agency

About this bridge

I 93 SB B16-SB4 over Comb Cambrige&mbta/Bmrr is a steel stringer/multi-beam or girder carrying I 93 SB B16-SB4 over Comb Cambrige&mbta/Bmrr in Suffolk County, Massachusetts. It was built in 1970, so it is 55 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 77,596 vehicles a day, roughly 12% of them trucks, projected to reach 119,869 by 2032. The structure is 1,214 ft (370 m) long and 71 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI 93 SB B16-SB4
CrossesComb Cambrige&mbta/Bmrr
Location1.2 MI N of JCT I93&US1
RouteInterstate 93
CountySuffolk County
StateMassachusetts
Coordinates42.38311, -71.07679
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.
Last inspectionJuly 2023
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 alignment7: Better than present minimum criteria
Operating rating61.3 US tons
Inventory rating36.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans11
Design loadHS 20
Structure length1,214 ft (370 m)
Longest span212 ft (64.6 m)
Deck width71 ft (21.7 m)
Roadway width65 ft (19.8 m)
Vertical clearance over deck15 ft (4.6 m)

Traffic and service

Average daily traffic77,596 (2022)
Projected traffic119,869 by 2032
Trucks12%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and railroad
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$78.4 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 93 SB B16-SB4 over Comb Cambrige&mbta/Bmrr built?

It was built in 1970, making it 55 years old in 2025.

What condition is I 93 SB B16-SB4 over Comb Cambrige&mbta/Bmrr 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 SB B16-SB4 over Comb Cambrige&mbta/Bmrr carry?

About 77,596 vehicles per day (2022 count), of which roughly 12% are trucks.

How long is I 93 SB B16-SB4 over Comb Cambrige&mbta/Bmrr?

The structure is 1,214 ft (370 m) long with a longest span of 212 ft (64.6 m) and a deck 71 ft wide.

Who owns I 93 SB B16-SB4 over Comb Cambrige&mbta/Bmrr?

It is owned by the State Highway Agency.