US Bridges

ST 99 Nb/Broadway over RR Mbta/Bmrr/Csx

Fair

Middlesex County, Massachusetts · 30 M S of JCT SR16&SR99 · Structure no. E120073GKDOT634

Built
1956
69 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
111 ft
1 main span
Daily traffic
28,000
2024 count
Owner
State
State Highway Agency

About this bridge

ST 99 Nb/Broadway over RR Mbta/Bmrr/Csx is a steel stringer/multi-beam or girder carrying ST 99 Nb/Broadway over RR Mbta/Bmrr/Csx in Middlesex County, Massachusetts. It was built in 1956, so it is 69 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 28,000 vehicles a day, roughly 10% of them trucks, projected to reach 36,324 by 2031. The structure is 111 ft (33.8 m) long and 51 ft wide. If it were closed, the detour would be 4.3 mi (7 km).

Location

Open in Google Maps
CarriesST 99 Nb/Broadway
CrossesRR Mbta/Bmrr/Csx
Location30 M S of JCT SR16&SR99
RouteState Highway 99
CountyMiddlesex County
StateMassachusetts
Coordinates42.40163, -71.06027
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.
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 inspectionAugust 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 geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment6: Equal to present minimum criteria
Operating rating61.7 US tons
Inventory rating41 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length111 ft (33.8 m)
Longest span107 ft (32.6 m)
Deck width51 ft (15.5 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic28,000 (2024)
Projected traffic36,324 by 2031
Trucks10%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway and pedestrian
CrossesRailroad
Detour if closed4.3 mi (7 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$5.1 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was ST 99 Nb/Broadway over RR Mbta/Bmrr/Csx built?

It was built in 1956, making it 69 years old in 2025.

What condition is ST 99 Nb/Broadway over RR Mbta/Bmrr/Csx 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 August 2024.

How much traffic does ST 99 Nb/Broadway over RR Mbta/Bmrr/Csx carry?

About 28,000 vehicles per day (2024 count), of which roughly 10% are trucks.

How long is ST 99 Nb/Broadway over RR Mbta/Bmrr/Csx?

The structure is 111 ft (33.8 m) long with a longest span of 107 ft (32.6 m) and a deck 51 ft wide.

Who owns ST 99 Nb/Broadway over RR Mbta/Bmrr/Csx?

It is owned by the State Highway Agency.