US Bridges

SR 51 over 20th ST Southbound

Fair

Maricopa County, Arizona · 20th ST & SR 51 · Structure no. 02417

Built
1990
35 years old
Condition
Fair
inspected December 2023
Type
Box Beam or Girders - Single or Spread
Prestressed Concrete
Length
122 ft
1 main span
Daily traffic
180,062
2022 count
Owner
State
State Highway Agency

About this bridge

SR 51 over 20th ST Southbound is a prestressed concrete box beam or girders - single or spread carrying SR 51 over 20th ST Southbound in Maricopa County, Arizona. It was built in 1990, so it is 35 years old, younger than the Arizona average of 47.8 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 180,062 vehicles a day, roughly 7% of them trucks, projected to reach 180,072 by 2042. The structure is 122 ft (37.2 m) long and 129 ft wide.

Location

Open in Google Maps
CarriesSR 51
Crosses20th ST Southbound
Location20th ST & SR 51
RouteState Highway 51
CountyMaricopa County
StateArizona
Coordinates33.48244, -112.03916
Functional classUrban Principal Arterial - Other Freeway or Expressway

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating88 US tons
Inventory rating52 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length122 ft (37.2 m)
Longest span113 ft (34.4 m)
Deck width129 ft (39.4 m)
Roadway width124 ft (37.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic180,062 (2022)
Projected traffic180,072 by 2042
Trucks7%
Lanes on structure8
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed—
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 51 over 20th ST Southbound built?

It was built in 1990, making it 35 years old in 2025.

What condition is SR 51 over 20th ST Southbound 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 December 2023.

How much traffic does SR 51 over 20th ST Southbound carry?

About 180,062 vehicles per day (2022 count), of which roughly 7% are trucks.

How long is SR 51 over 20th ST Southbound?

The structure is 122 ft (37.2 m) long with a longest span of 113 ft (34.4 m) and a deck 129 ft wide.

Who owns SR 51 over 20th ST Southbound?

It is owned by the State Highway Agency.