US Bridges

I-10 over St. Marys RD

Fair

Pima County, Arizona · 2.7 MI N JCT I-19 · Structure no. 02186

Built
2009
16 years old
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
214 ft
2 main spans
Daily traffic
195,068
2022 count
Owner
State
State Highway Agency

About this bridge

I-10 over St. Marys RD is a prestressed concrete continuous stringer/multi-beam or girder carrying I-10 over St. Marys RD in Pima County, Arizona. It was built in 2009, so it is 16 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 195,068 vehicles a day, roughly 9% of them trucks, projected to reach 195,078 by 2042. The structure is 214 ft (65.2 m) long and 173 ft wide.

Location

Open in Google Maps
CarriesI-10
CrossesSt. Marys RD
Location2.7 MI N JCT I-19
RouteInterstate 10
CountyPima County
StateArizona
Coordinates32.2297, -110.9825
Functional classUrban Principal Arterial - Interstate

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating82 US tons
Inventory rating46 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length214 ft (65.2 m)
Longest span104 ft (31.7 m)
Deck width173 ft (52.7 m)
Roadway width166 ft (50.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic195,068 (2022)
Projected traffic195,078 by 2042
Trucks9%
Lanes on structure10
Traffic directionTwo-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed—
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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 I-10 over St. Marys RD built?

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

What condition is I-10 over St. Marys RD 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 2024.

How much traffic does I-10 over St. Marys RD carry?

About 195,068 vehicles per day (2022 count), of which roughly 9% are trucks.

How long is I-10 over St. Marys RD?

The structure is 214 ft (65.2 m) long with a longest span of 104 ft (31.7 m) and a deck 173 ft wide.

Who owns I-10 over St. Marys RD?

It is owned by the State Highway Agency.