US Bridges

FM 646 over Willow Bayou

Good

Galveston County, Texas · 0.4 MI N of FM 2004 · Structure no. 120850252303343

Built
2024
1 years old
Condition
Good
inspected October 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
70 ft
1 main span
Daily traffic
3,317
2023 count
Owner
State
State Highway Agency

About this bridge

FM 646 over Willow Bayou is a prestressed concrete stringer/multi-beam or girder carrying FM 646 over Willow Bayou in Galveston County, Texas. It was built in 2024, so it is 1 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 9 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 3,317 vehicles a day, roughly 53% of them trucks, projected to reach 1 by 1900. The structure is 70 ft (21.3 m) long and 49 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesFM 646
CrossesWillow Bayou
Location0.4 MI N of FM 2004
RouteState Highway 646
CountyGalveston County
StateTexas
Coordinates29.32052, -95.0807
Functional classRural Principal Arterial - Other

Condition and inspection

Good

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

ComponentRatingMeaning
Deck9 ExcellentNo problems noted.
Superstructure9 ExcellentNo problems noted.
Substructure9 ExcellentNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour evaluation has not been made
Structural evaluation9: Superior to present desirable 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 typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHL 93
Structure length70 ft (21.3 m)
Longest span70 ft (21.3 m)
Deck width49 ft (14.8 m)
Roadway width46 ft (14 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,317 (2023)
Projected traffic1 by 1900
Trucks53%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 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 Willow Bayou built?

It was built in 2024, making it 1 years old in 2025.

What condition is FM 646 over Willow Bayou 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 Willow Bayou carry?

About 3,317 vehicles per day (2023 count), of which roughly 53% are trucks.

How long is FM 646 over Willow Bayou?

The structure is 70 ft (21.3 m) long with a longest span of 70 ft (21.3 m) and a deck 49 ft wide.

Who owns FM 646 over Willow Bayou?

It is owned by the State Highway Agency.