US Bridges

FM 646 over Briscoe Canal

Good

Galveston County, Texas · 1.19 MI N of FM 1764 · Structure no. 120850097801056

Built
2011
14 years old
Condition
Good
inspected October 2024
Type
Culvert
Concrete
Length
22 ft
3 main spans
Daily traffic
13,321
2020 count
Owner
State
State Highway Agency

About this bridge

FM 646 over Briscoe Canal is a concrete culvert carrying FM 646 over Briscoe Canal in Galveston County, Texas. It was built in 2011, so it is 14 years old, younger than the Texas average of 44.4 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 13,321 vehicles a day, roughly 3% of them trucks, projected to reach 26,600 by 2030. The structure is 22 ft (6.7 m) long and 86 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesFM 646
CrossesBriscoe Canal
Location1.19 MI N of FM 1764
RouteState Highway 646
CountyGalveston County
StateTexas
Coordinates29.40797, -95.09215
Functional classUrban Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert7 GoodSome minor problems.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
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 typeCulvert
MaterialConcrete
DeckNot applicable
Main spans3
Design loadHL 93
Structure length22 ft (6.7 m)
Longest span6 ft (1.8 m)
Deck width86 ft (26.2 m)
Roadway width66 ft (20.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,321 (2020)
Projected traffic26,600 by 2030
Trucks3%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM 646 over Briscoe Canal built?

It was built in 2011, making it 14 years old in 2025.

What condition is FM 646 over Briscoe Canal in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in October 2024.

How much traffic does FM 646 over Briscoe Canal carry?

About 13,321 vehicles per day (2020 count), of which roughly 3% are trucks.

How long is FM 646 over Briscoe Canal?

The structure is 22 ft (6.7 m) long with a longest span of 6 ft (1.8 m) and a deck 86 ft wide.

Who owns FM 646 over Briscoe Canal?

It is owned by the State Highway Agency.