US Bridges

ST 1 A/On Ramp over Other Relief

Fair

Suffolk County, Massachusetts · 1.4 KM NE of Sumner Tun · Structure no. B1623639MDOTNBI

Built
1951
74 years old, rebuilt 1977
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
426 ft
6 main spans
Daily traffic
15,000
2024 count
Owner
State
State Highway Agency

About this bridge

ST 1 A/On Ramp over Other Relief is a steel stringer/multi-beam or girder carrying ST 1 A/On Ramp over Other Relief 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 6 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 15,000 vehicles a day, roughly 3% of them trucks, projected to reach 24,479 by 2033. The structure is 426 ft (129.8 m) long and 30 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesST 1 A/On Ramp
CrossesOther Relief
Location1.4 KM NE of Sumner Tun
RouteState Highway 1A
CountySuffolk County
StateMassachusetts
Coordinates42.3793, -71.02569
Functional classUrban Minor 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating69.2 US tons
Inventory rating41.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length426 ft (129.8 m)
Longest span88 ft (26.8 m)
Deck width30 ft (9.1 m)
Roadway width25 ft (7.7 m)
Vertical clearance over deck18 ft (5.5 m)

Traffic and service

Average daily traffic15,000 (2024)
Projected traffic24,479 by 2033
Trucks3%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesOther
Detour if closed1.9 mi (3 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 proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$610,000 (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was ST 1 A/On Ramp over Other Relief built?

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

What condition is ST 1 A/On Ramp 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 January 2024.

How much traffic does ST 1 A/On Ramp over Other Relief carry?

About 15,000 vehicles per day (2024 count), of which roughly 3% are trucks.

How long is ST 1 A/On Ramp over Other Relief?

The structure is 426 ft (129.8 m) long with a longest span of 88 ft (26.8 m) and a deck 30 ft wide.

Who owns ST 1 A/On Ramp over Other Relief?

It is owned by the State Highway Agency.