US Bridges

SP 421 over Zarzamora Creek

Good

Bexar County, Texas · 0.2 MI SE of IH 410 · Structure no. 150150029110187

Built
1981
44 years old, rebuilt 2002
Condition
Good
inspected August 2024
Type
Culvert
Concrete
Length
71 ft
6 main spans
Daily traffic
28,144
2020 count
Owner
State
State Highway Agency

About this bridge

SP 421 over Zarzamora Creek is a concrete culvert carrying SP 421 over Zarzamora Creek in Bexar County, Texas. It was built in 1981 and reconstructed in 2002, so it is 44 years old, younger than the Texas average of 44.4 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 28,144 vehicles a day, roughly 7% of them trucks, projected to reach 41,390 by 2033. The structure is 71 ft (21.6 m) long and 99 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesSP 421
CrossesZarzamora Creek
Location0.2 MI SE of IH 410
RouteState Highway 421
CountyBexar County
StateTexas
Coordinates29.48147, -98.59706
Functional classUrban Other Principal Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert7 GoodSome minor problems.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44 US tons
Inventory rating26 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length71 ft (21.6 m)
Longest span10 ft (3 m)
Deck width99 ft (30.1 m)
Roadway width82 ft (25.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic28,144 (2020)
Projected traffic41,390 by 2033
Trucks7%
Lanes on structure7
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost$15,000
NavigationNo navigation control on waterway

Frequently asked questions

When was SP 421 over Zarzamora Creek built?

It was built in 1981, making it 44 years old in 2025. It was reconstructed in 2002.

What condition is SP 421 over Zarzamora Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in August 2024.

How much traffic does SP 421 over Zarzamora Creek carry?

About 28,144 vehicles per day (2020 count), of which roughly 7% are trucks.

How long is SP 421 over Zarzamora Creek?

The structure is 71 ft (21.6 m) long with a longest span of 10 ft (3 m) and a deck 99 ft wide.

Who owns SP 421 over Zarzamora Creek?

It is owned by the State Highway Agency.