US Bridges

US 181 over San Antonio River

Fair

Karnes County, Texas · 0.5 MI SE of FM 791 · Structure no. 161290010005081

Built
1961
64 years old, rebuilt 1991
Condition
Fair
inspected April 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
533 ft
3 main spans
Daily traffic
6,786
2022 count
Owner
State
State Highway Agency

About this bridge

US 181 over San Antonio River is a steel continuous stringer/multi-beam or girder carrying US 181 over San Antonio River in Karnes County, Texas. It was built in 1961 and reconstructed in 1991, so it is 64 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 6,786 vehicles a day, roughly 24% of them trucks, projected to reach 9,500 by 2042. The structure is 533 ft (162.5 m) long and 46 ft wide. If it were closed, the detour would be 18 mi (29 km).

Location

Open in Google Maps
CarriesUS 181
CrossesSan Antonio River
Location0.5 MI SE of FM 791
RouteU.S. Route 181
CountyKarnes County
StateTexas
Coordinates28.97746, -98.01031
Functional classRural Principal Arterial - Other

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating41 US tons
Inventory rating24 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3 (+10 approach)
Design loadH 20
Structure length533 ft (162.5 m)
Longest span90 ft (27.4 m)
Deck width46 ft (14 m)
Roadway width43 ft (13.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,786 (2022)
Projected traffic9,500 by 2042
Trucks24%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed18 mi (29 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 181 over San Antonio River built?

It was built in 1961, making it 64 years old in 2025. It was reconstructed in 1991.

What condition is US 181 over San Antonio 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 April 2024.

How much traffic does US 181 over San Antonio River carry?

About 6,786 vehicles per day (2022 count), of which roughly 24% are trucks.

How long is US 181 over San Antonio River?

The structure is 533 ft (162.5 m) long with a longest span of 90 ft (27.4 m) and a deck 46 ft wide.

Who owns US 181 over San Antonio River?

It is owned by the State Highway Agency.