US Bridges

HWY ST Marys ST over Comb I 90 & Mbta/Csx

Fair

Suffolk County, Massachusetts · .32 KM S. Charles Rv S49 · Structure no. B162164T1DOTNBI

Built
1965
60 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
175 ft
3 main spans
Daily traffic
2,974
2024 count
Owner
State
State Highway Agency

About this bridge

HWY ST Marys ST over Comb I 90 & Mbta/Csx is a steel stringer/multi-beam or girder carrying HWY ST Marys ST over Comb I 90 & Mbta/Csx in Suffolk County, Massachusetts. It was built in 1965, so it is 60 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 2,974 vehicles a day, roughly 5% of them trucks, projected to reach 4,738 by 2031. The structure is 175 ft (53.3 m) long and 42 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesHWY ST Marys ST
CrossesComb I 90 & Mbta/Csx
Location.32 KM S. Charles Rv S49
RouteInterstate 90
CountySuffolk County
StateMassachusetts
Coordinates42.34895, -71.10678
Functional classUrban Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment8: Equal to present desirable criteria
Operating rating40.8 US tons
Inventory rating36.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length175 ft (53.3 m)
Longest span69 ft (20.9 m)
Deck width42 ft (12.9 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,974 (2024)
Projected traffic4,738 by 2031
Trucks5%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway and pedestrian
CrossesHighway and railroad
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo
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 proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$10.9 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was HWY ST Marys ST over Comb I 90 & Mbta/Csx built?

It was built in 1965, making it 60 years old in 2025.

What condition is HWY ST Marys ST over Comb I 90 & Mbta/Csx 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 August 2024.

How much traffic does HWY ST Marys ST over Comb I 90 & Mbta/Csx carry?

About 2,974 vehicles per day (2024 count), of which roughly 5% are trucks.

How long is HWY ST Marys ST over Comb I 90 & Mbta/Csx?

The structure is 175 ft (53.3 m) long with a longest span of 69 ft (20.9 m) and a deck 42 ft wide.

Who owns HWY ST Marys ST over Comb I 90 & Mbta/Csx?

It is owned by the State Highway Agency.