US Bridges

Gwmp over Pimmit Run

Fair

Fairfax County, Virginia · 4.6 Miles South of I-495. · Structure no. 3300005P0000000

Built
1959
66 years old, rebuilt 1993
Condition
Fair
inspected April 2023
Type
Girder and Floorbeam System
Steel Continuous
Length
353 ft
3 main spans
Daily traffic
27,400
2007 count
Owner
Federal
National Park Service

About this bridge

Gwmp over Pimmit Run is a steel continuous girder and floorbeam system carrying Gwmp over Pimmit Run in Fairfax County, Virginia. It was built in 1959 and reconstructed in 1993, so it is 66 years old, older than the Virginia average of 50.7 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 27,400 vehicles a day, roughly 1% of them trucks, projected to reach 30,140 by 2027. The structure is 353 ft (107.6 m) long and 68 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

Open in Google Maps
CarriesGwmp
CrossesPimmit Run
Location4.6 Miles South of I-495.
RouteFederal Lands Road 1
CountyFairfax County
StateVirginia
Coordinates38.93194, -77.12411
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionApril 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 geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48.9 US tons
Inventory rating29 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel Continuous
DeckConcrete, precast panels
Main spans3
Design loadH 20
Structure length353 ft (107.6 m)
Longest span131 ft (39.9 m)
Deck width68 ft (20.7 m)
Roadway width63 ft (19.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic27,400 (2007)
Projected traffic30,140 by 2027
Trucks1%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.7 mi (14 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerNational Park Service
Maintained byNational Park Service
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$12,000 (2021 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Gwmp over Pimmit Run built?

It was built in 1959, making it 66 years old in 2025. It was reconstructed in 1993.

What condition is Gwmp over Pimmit Run 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 April 2023.

How much traffic does Gwmp over Pimmit Run carry?

About 27,400 vehicles per day (2007 count), of which roughly 1% are trucks.

How long is Gwmp over Pimmit Run?

The structure is 353 ft (107.6 m) long with a longest span of 131 ft (39.9 m) and a deck 68 ft wide.

Who owns Gwmp over Pimmit Run?

It is owned by the National Park Service.