US Bridges

SH 121 SB over Sister Grove Branch

Fair

Collin County, Texas · 4.10 MI NE of FM 545 · Structure no. 180430054903232

Built
2021
4 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
220 ft
3 main spans
Daily traffic
15,070
2020 count
Owner
State
State Highway Agency

About this bridge

SH 121 SB over Sister Grove Branch is a prestressed concrete stringer/multi-beam or girder carrying SH 121 SB over Sister Grove Branch in Collin County, Texas. It was built in 2021, so it is 4 years old, younger 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 15,070 vehicles a day, roughly 10% of them trucks, projected to reach 22,900 by 2040. The structure is 220 ft (67.1 m) long and 40 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesSH 121 SB
CrossesSister Grove Branch
Location4.10 MI NE of FM 545
RouteState Highway 121
CountyCollin County
StateTexas
Coordinates33.31779, -96.50466
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy9: Superior to present desirable 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, cast-in-place
Main spans3 (+3 approach)
Design loadHL 93
Structure length220 ft (67.1 m)
Longest span100 ft (30.5 m)
Deck width40 ft (12.2 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15,070 (2020)
Projected traffic22,900 by 2040
Trucks10%
Lanes on structure2
Traffic directionOne-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 SH 121 SB over Sister Grove Branch built?

It was built in 2021, making it 4 years old in 2025.

What condition is SH 121 SB over Sister Grove Branch 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 September 2023.

How much traffic does SH 121 SB over Sister Grove Branch carry?

About 15,070 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is SH 121 SB over Sister Grove Branch?

The structure is 220 ft (67.1 m) long with a longest span of 100 ft (30.5 m) and a deck 40 ft wide.

Who owns SH 121 SB over Sister Grove Branch?

It is owned by the State Highway Agency.