US Bridges

ST 1 A/Nb over Other Relief

Fair

Suffolk County, Massachusetts · 2000 Ft NE Callahan Tun · Structure no. B1623539VDOTNBI

Built
1951
74 years old, rebuilt 2005
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
204 ft
3 main spans
Daily traffic
29,117
2023 count
Owner
State
State Highway Agency

About this bridge

ST 1 A/Nb over Other Relief is a steel stringer/multi-beam or girder carrying ST 1 A/Nb over Other Relief in Suffolk County, Massachusetts. It was built in 1951 and reconstructed in 2005, 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 29,117 vehicles a day, roughly 4% of them trucks, projected to reach 33,007 by 2031. The structure is 204 ft (62.2 m) long and 45 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesST 1 A/Nb
CrossesOther Relief
Location2000 Ft NE Callahan Tun
RouteState Highway 1A
CountySuffolk County
StateMassachusetts
Coordinates42.37253, -71.03428
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating71.9 US tons
Inventory rating43.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length204 ft (62.2 m)
Longest span74 ft (22.6 m)
Deck width45 ft (13.7 m)
Roadway width41 ft (12.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic29,117 (2023)
Projected traffic33,007 by 2031
Trucks4%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
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$8.4 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was ST 1 A/Nb over Other Relief built?

It was built in 1951, making it 74 years old in 2025. It was reconstructed in 2005.

What condition is ST 1 A/Nb over Other Relief 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/Nb over Other Relief carry?

About 29,117 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is ST 1 A/Nb over Other Relief?

The structure is 204 ft (62.2 m) long with a longest span of 74 ft (22.6 m) and a deck 45 ft wide.

Who owns ST 1 A/Nb over Other Relief?

It is owned by the State Highway Agency.