US Bridges

I 495 NB over ST110 /ST113/MERRIMACK

Poor

Essex County, Massachusetts · At Merrimac River · Structure no. M170312XHDOTNBI

Built
1963
62 years old
Condition
Poor
inspected April 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
173 ft
3 main spans
Daily traffic
58,225
2024 count
Owner
State
State Highway Agency

About this bridge

I 495 NB over ST110 /ST113/MERRIMACK is a steel stringer/multi-beam or girder carrying I 495 NB over ST110 /ST113/MERRIMACK in Essex County, Massachusetts. It was built in 1963, so it is 62 years old, younger than the Massachusetts average of 63.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 3 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: open, would be posted or closed except for temporary shoring.

It carries about 58,225 vehicles a day, roughly 10% of them trucks, projected to reach 80,623 by 2032. The structure is 173 ft (52.6 m) long and 52 ft wide. If it were closed, the detour would be 4.3 mi (7 km).

Location

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CarriesI 495 NB
CrossesST110 /ST113/MERRIMACK
LocationAt Merrimac River
RouteInterstate 495
CountyEssex County
StateMassachusetts
Coordinates42.75322, -71.1288
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2024
Inspection intervalevery 6 months
Operating statusOpen, would be posted or closed except for temporary shoring
ScourBridge not over waterway
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment7: Better than present minimum criteria
Operating rating63.1 US tons
Inventory rating37.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length173 ft (52.6 m)
Longest span68 ft (20.7 m)
Deck width52 ft (15.9 m)
Roadway width46 ft (14 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic58,225 (2024)
Projected traffic80,623 by 2032
Trucks10%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed4.3 mi (7 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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$8.2 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 495 NB over ST110 /ST113/MERRIMACK built?

It was built in 1963, making it 62 years old in 2025.

What condition is I 495 NB over ST110 /ST113/MERRIMACK in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in April 2024.

How much traffic does I 495 NB over ST110 /ST113/MERRIMACK carry?

About 58,225 vehicles per day (2024 count), of which roughly 10% are trucks.

How long is I 495 NB over ST110 /ST113/MERRIMACK?

The structure is 173 ft (52.6 m) long with a longest span of 68 ft (20.7 m) and a deck 52 ft wide.

Who owns I 495 NB over ST110 /ST113/MERRIMACK?

It is owned by the State Highway Agency.