US Bridges

FM 521 over San Bernard River

Fair

Brazoria County, Texas · 2.50 MI S of SH 36 · Structure no. 120200100401006

Built
1960
65 years old, rebuilt 2005
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
881 ft
3 main spans
Daily traffic
9,726
2016 count
Owner
State
State Highway Agency

About this bridge

FM 521 over San Bernard River is a steel continuous stringer/multi-beam or girder carrying FM 521 over San Bernard River in Brazoria County, Texas. It was built in 1960 and reconstructed in 2005, so it is 65 years old, older 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 9,726 vehicles a day, roughly 4% of them trucks, projected to reach 8,960 by 2033. The structure is 881 ft (268.5 m) long and 46 ft wide. If it were closed, the detour would be 14.9 mi (24 km).

Location

Open in Google Maps
CarriesFM 521
CrossesSan Bernard River
Location2.50 MI S of SH 36
RouteState Highway 521
CountyBrazoria County
StateTexas
Coordinates29.01105, -95.58823
Functional classRural Major 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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating47 US tons
Inventory rating28 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3 (+9 approach)
Design loadOther
Structure length881 ft (268.5 m)
Longest span140 ft (42.7 m)
Deck width46 ft (14 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,726 (2016)
Projected traffic8,960 by 2033
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.9 mi (24 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$613,000
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was FM 521 over San Bernard River built?

It was built in 1960, making it 65 years old in 2025. It was reconstructed in 2005.

What condition is FM 521 over San Bernard River 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 December 2024.

How much traffic does FM 521 over San Bernard River carry?

About 9,726 vehicles per day (2016 count), of which roughly 4% are trucks.

How long is FM 521 over San Bernard River?

The structure is 881 ft (268.5 m) long with a longest span of 140 ft (42.7 m) and a deck 46 ft wide.

Who owns FM 521 over San Bernard River?

It is owned by the State Highway Agency.