US Bridges

SR 51 over 20th Street Northbound

Fair

Maricopa County, Arizona · 20th Street and SR 51 · Structure no. 02429

Built
1990
35 years old
Condition
Fair
inspected December 2023
Type
Box Beam or Girders - Single or Spread
Prestressed Concrete
Length
144 ft
1 main span
Daily traffic
180,704
2022 count
Owner
State
State Highway Agency

About this bridge

SR 51 over 20th Street Northbound is a prestressed concrete box beam or girders - single or spread carrying SR 51 over 20th Street Northbound 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 180,704 vehicles a day, roughly 7% of them trucks, projected to reach 180,714 by 2042. The structure is 144 ft (43.9 m) long and 129 ft wide.

Location

Open in Google Maps
CarriesSR 51
Crosses20th Street Northbound
Location20th Street and SR 51
RouteState Highway 51
CountyMaricopa County
StateArizona
Coordinates33.4777, -112.0383
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 rating99 US tons
Inventory rating63.1 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length144 ft (43.9 m)
Longest span132 ft (40.2 m)
Deck width129 ft (39.4 m)
Roadway width124 ft (37.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic180,704 (2022)
Projected traffic180,714 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 Street Northbound built?

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

What condition is SR 51 over 20th Street Northbound 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 Street Northbound carry?

About 180,704 vehicles per day (2022 count), of which roughly 7% are trucks.

How long is SR 51 over 20th Street Northbound?

The structure is 144 ft (43.9 m) long with a longest span of 132 ft (40.2 m) and a deck 129 ft wide.

Who owns SR 51 over 20th Street Northbound?

It is owned by the State Highway Agency.