US Bridges

ST 9 Boylston ST over Water Charles River

Fair

Middlesex County, Massachusetts · Newton-Wellesley Twn Line · Structure no. N120042EBDOTNBI

Built
1900
125 years old, rebuilt 1932
Condition
Fair
inspected June 2023
Type
Arch - Deck
Concrete
Length
76 ft
2 main spans
Daily traffic
51,270
2022 count
Owner
State
State Highway Agency

About this bridge

ST 9 Boylston ST over Water Charles River is a concrete arch - deck carrying ST 9 Boylston ST over Water Charles River in Middlesex County, Massachusetts. It was built in 1900 and reconstructed in 1932, so it is 125 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 51,270 vehicles a day, roughly 4% of them trucks, projected to reach 208,468 by 2032. The structure is 76 ft (23.2 m) long and 161 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesST 9 Boylston ST
CrossesWater Charles River
LocationNewton-Wellesley Twn Line
RouteState Highway 9
CountyMiddlesex County
StateMassachusetts
Coordinates42.31691, -71.22805
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating110.1 US tons
Inventory rating110.1 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckNot applicable
Main spans2
Design loadH 20
Structure length76 ft (23.2 m)
Longest span50 ft (15.2 m)
Deck width161 ft (49.1 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic51,270 (2022)
Projected traffic208,468 by 2032
Trucks4%
Lanes on structure6
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusListed on the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$11.5 million (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was ST 9 Boylston ST over Water Charles River built?

It was built in 1900, making it 125 years old in 2025. It was reconstructed in 1932.

What condition is ST 9 Boylston 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 June 2023.

How much traffic does ST 9 Boylston ST over Water Charles River carry?

About 51,270 vehicles per day (2022 count), of which roughly 4% are trucks.

How long is ST 9 Boylston ST over Water Charles River?

The structure is 76 ft (23.2 m) long with a longest span of 50 ft (15.2 m) and a deck 161 ft wide.

Who owns ST 9 Boylston ST over Water Charles River?

It is owned by the State Highway Agency.