US Bridges

Thryra Johnson RD over San Miguel Bayou

Fair

Sabine Parish, Louisiana · Thyra Johnson Road · Structure no. 084331489932951

Built
1993
32 years old
Condition
Fair
inspected January 2025
Type
Culvert
Steel
Length
32 ft
3 main spans
Daily traffic
120
2022 count
Owner
County
County Highway Agency

About this bridge

Thryra Johnson RD over San Miguel Bayou is a steel culvert carrying Thryra Johnson RD over San Miguel Bayou in Sabine Parish, Louisiana. It was built in 1993, so it is 32 years old, younger than the Louisiana average of 43 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 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 120 vehicles a day, projected to reach 132 by 2042. The structure is 32 ft (9.8 m) long and 38 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesThryra Johnson RD
CrossesSan Miguel Bayou
LocationThyra Johnson Road
RouteCounty Highway 0
CountySabine Parish
StateLouisiana
Coordinates31.81613, -93.4907
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment4: Meets minimum tolerable limits to be left in place as is
Operating rating48.9 US tons
Inventory rating37.8 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans3
Design loadHS 20
Structure length32 ft (9.8 m)
Longest span8 ft (2.4 m)
Deck width38 ft (11.6 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic120 (2022)
Projected traffic132 by 2042
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 Thryra Johnson RD over San Miguel Bayou built?

It was built in 1993, making it 32 years old in 2025.

What condition is Thryra Johnson RD over San Miguel Bayou 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 January 2025.

How much traffic does Thryra Johnson RD over San Miguel Bayou carry?

About 120 vehicles per day (2022 count).

How long is Thryra Johnson RD over San Miguel Bayou?

The structure is 32 ft (9.8 m) long with a longest span of 8 ft (2.4 m) and a deck 38 ft wide.

Who owns Thryra Johnson RD over San Miguel Bayou?

It is owned by the County Highway Agency.