US Bridges

FM 646 over Hl&p Discharge Canal

Fair

Galveston County, Texas · 2.5 MI E of SH146/FM646 · Structure no. 120850097802011

Built
1994
31 years old
Condition
Fair
inspected August 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
195 ft
3 main spans
Daily traffic
8,809
2020 count
Owner
State
State Highway Agency

About this bridge

FM 646 over Hl&p Discharge Canal is a prestressed concrete box beam or girders - multiple carrying FM 646 over Hl&p Discharge Canal in Galveston County, Texas. It was built in 1994, so it is 31 years old, younger than the Texas average of 44.4 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 8,809 vehicles a day, roughly 6% of them trucks, projected to reach 10,390 by 2033. The structure is 195 ft (59.4 m) long and 54 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesFM 646
CrossesHl&p Discharge Canal
Location2.5 MI E of SH146/FM646
RouteState Highway 646
CountyGalveston County
StateTexas
Coordinates29.50525, -94.95937
Functional classUrban Minor 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection5 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
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating60 US tons
Inventory rating36 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans3
Design loadHS 20
Structure length195 ft (59.4 m)
Longest span73 ft (22.3 m)
Deck width54 ft (16.4 m)
Roadway width45 ft (13.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,809 (2020)
Projected traffic10,390 by 2033
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.1 mi (5 km)
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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM 646 over Hl&p Discharge Canal built?

It was built in 1994, making it 31 years old in 2025.

What condition is FM 646 over Hl&p Discharge Canal 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 FM 646 over Hl&p Discharge Canal carry?

About 8,809 vehicles per day (2020 count), of which roughly 6% are trucks.

How long is FM 646 over Hl&p Discharge Canal?

The structure is 195 ft (59.4 m) long with a longest span of 73 ft (22.3 m) and a deck 54 ft wide.

Who owns FM 646 over Hl&p Discharge Canal?

It is owned by the State Highway Agency.