US Bridges

ST 1 a over HWY Chelsea & Bremen S

Fair

Suffolk County, Massachusetts · 1000FT NE of Callhan Tun. · Structure no. B1623539TDOTNBI

Built
1951
74 years old, rebuilt 1977
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
380 ft
5 main spans
Daily traffic
56,669
2024 count
Owner
State
State Highway Agency

About this bridge

ST 1 a over HWY Chelsea & Bremen S is a steel stringer/multi-beam or girder carrying ST 1 a over HWY Chelsea & Bremen S in Suffolk County, Massachusetts. It was built in 1951 and reconstructed in 1977, so it is 74 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 56,669 vehicles a day, roughly 4% of them trucks, projected to reach 63,962 by 2031. The structure is 380 ft (115.8 m) long and 93 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesST 1 a
CrossesHWY Chelsea & Bremen S
Location1000FT NE of Callhan Tun.
RouteState Highway 1A
CountySuffolk County
StateMassachusetts
Coordinates42.37304, -71.03518
Functional classUrban Other Principal Arterial

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2024
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 geometry6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating65.8 US tons
Inventory rating39.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans5 (+4 approach)
Design loadHS 20
Structure length380 ft (115.8 m)
Longest span83 ft (25.3 m)
Deck width93 ft (28.4 m)
Roadway width88 ft (26.7 m)
Vertical clearance over deck17 ft (5.2 m)

Traffic and service

Average daily traffic56,669 (2024)
Projected traffic63,962 by 2031
Trucks4%
Lanes on structure6
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

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$32.1 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was ST 1 a over HWY Chelsea & Bremen S built?

It was built in 1951, making it 74 years old in 2025. It was reconstructed in 1977.

What condition is ST 1 a over HWY Chelsea & Bremen S 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 December 2024.

How much traffic does ST 1 a over HWY Chelsea & Bremen S carry?

About 56,669 vehicles per day (2024 count), of which roughly 4% are trucks.

How long is ST 1 a over HWY Chelsea & Bremen S?

The structure is 380 ft (115.8 m) long with a longest span of 83 ft (25.3 m) and a deck 93 ft wide.

Who owns ST 1 a over HWY Chelsea & Bremen S?

It is owned by the State Highway Agency.