US Bridges

West Portsmouth ST over I-93 US 4

Fair

Merrimack County, New Hampshire · 1.4 MI N. JCT 132 · Structure no. 005201250011800

Built
2000
25 years old
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
259 ft
2 main spans
Daily traffic
4,541
2023 count
Owner
State
State Highway Agency

About this bridge

West Portsmouth ST over I-93 US 4 is a steel continuous stringer/multi-beam or girder carrying West Portsmouth ST over I-93 US 4 in Merrimack County, New Hampshire. It was built in 2000, so it is 25 years old, younger than the New Hampshire average of 56.9 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 4,541 vehicles a day, roughly 3% of them trucks, projected to reach 6,720 by 2043. The structure is 259 ft (78.9 m) long and 64 ft wide.

Location

Open in Google Maps
CarriesWest Portsmouth ST
CrossesI-93 US 4
Location1.4 MI N. JCT 132
RouteState Highway 3B
CountyMerrimack County
StateNew Hampshire
Coordinates43.2368, -71.53899
Functional classUrban Collector

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating58 US tons
Inventory rating45.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 25 or greater
Structure length259 ft (78.9 m)
Longest span138 ft (42.1 m)
Deck width64 ft (19.5 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,541 (2023)
Projected traffic6,720 by 2043
Trucks3%
Lanes on structure3
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed—
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$314,000 (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was West Portsmouth ST over I-93 US 4 built?

It was built in 2000, making it 25 years old in 2025.

What condition is West Portsmouth ST over I-93 US 4 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 May 2023.

How much traffic does West Portsmouth ST over I-93 US 4 carry?

About 4,541 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is West Portsmouth ST over I-93 US 4?

The structure is 259 ft (78.9 m) long with a longest span of 138 ft (42.1 m) and a deck 64 ft wide.

Who owns West Portsmouth ST over I-93 US 4?

It is owned by the State Highway Agency.