US Bridges

SH 121 Nbml over FM 423

Fair

Denton County, Texas · 6.5 MI NE of IH 35E · Structure no. 180610036403173

Built
2009
16 years old, rebuilt 2020
Condition
Fair
inspected October 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
303 ft
1 main span
Daily traffic
25,000
2013 count
Owner
Toll Authority
Local Toll Authority

About this bridge

SH 121 Nbml over FM 423 is a prestressed concrete stringer/multi-beam or girder carrying SH 121 Nbml over FM 423 in Denton County, Texas. It was built in 2009 and reconstructed in 2020, so it is 16 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 25,000 vehicles a day, roughly 7% of them trucks, projected to reach 33,409 by 2033. The structure is 303 ft (92.4 m) long and 83 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesSH 121 Nbml
CrossesFM 423
Location6.5 MI NE of IH 35E
CountyDenton County
StateTexas
Coordinates33.06563, -96.88885
Functional classUrban Other Principal Arterial

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.
Last inspectionOctober 2023
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: 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, cast-in-place
Main spans1 (+2 approach)
Design loadHS 20
Structure length303 ft (92.4 m)
Longest span127 ft (38.7 m)
Deck width83 ft (25.4 m)
Roadway width73 ft (22.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic25,000 (2013)
Projected traffic33,409 by 2033
Trucks7%
Lanes on structure5
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a toll road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerLocal Toll Authority
Maintained byLocal Toll Authority
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was SH 121 Nbml over FM 423 built?

It was built in 2009, making it 16 years old in 2025. It was reconstructed in 2020.

What condition is SH 121 Nbml over FM 423 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 October 2023.

How much traffic does SH 121 Nbml over FM 423 carry?

About 25,000 vehicles per day (2013 count), of which roughly 7% are trucks.

How long is SH 121 Nbml over FM 423?

The structure is 303 ft (92.4 m) long with a longest span of 127 ft (38.7 m) and a deck 83 ft wide.

Who owns SH 121 Nbml over FM 423?

It is owned by the Local Toll Authority.