US Bridges

US 20 N Beacon ST over Water Charles River

Fair

Suffolk County, Massachusetts · .1 MI N of I 90 · Structure no. B160144F8DOTNBI

Built
1915
110 years old
Condition
Fair
inspected July 2023
Type
Arch - Deck
Concrete
Length
205 ft
3 main spans
Daily traffic
26,400
2023 count
Owner
State
State Highway Agency

About this bridge

US 20 N Beacon ST over Water Charles River is a concrete arch - deck carrying US 20 N Beacon ST over Water Charles River in Suffolk County, Massachusetts. It was built in 1915, so it is 110 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 26,400 vehicles a day, roughly 4% of them trucks, projected to reach 48,169 by 2032. The structure is 205 ft (62.5 m) long and 79 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesUS 20 N Beacon ST
CrossesWater Charles River
Location.1 MI N of I 90
RouteU.S. Route 20
CountySuffolk County
StateMassachusetts
Coordinates42.35898, -71.16154
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
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.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
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
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment4: Meets minimum tolerable limits to be left in place as is
Operating rating100.6 US tons
Inventory rating60.3 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckNot applicable
Main spans3
Design loadH 20
Structure length205 ft (62.5 m)
Longest span75 ft (22.9 m)
Deck width79 ft (24.1 m)
Roadway width54 ft (16.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic26,400 (2023)
Projected traffic48,169 by 2032
Trucks4%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
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 statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$14.8 million (2025 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was US 20 N Beacon ST over Water Charles River built?

It was built in 1915, making it 110 years old in 2025.

What condition is US 20 N Beacon ST over Water Charles River 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 US 20 N Beacon ST over Water Charles River carry?

About 26,400 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is US 20 N Beacon ST over Water Charles River?

The structure is 205 ft (62.5 m) long with a longest span of 75 ft (22.9 m) and a deck 79 ft wide.

Who owns US 20 N Beacon ST over Water Charles River?

It is owned by the State Highway Agency.