US Bridges

SMA3613;MCMILLAN over Phyllis Canal

Fair

Ada County, Idaho · 3.0 S. 0.3 W. Star · Structure no. 000000000025850

Built
1967
58 years old
Condition
Fair
inspected March 2023
Type
Tee Beam
Prestressed Concrete
Length
38 ft
1 main span
Daily traffic
1,300
2023 count
Owner
County
County Highway Agency

About this bridge

SMA3613;MCMILLAN over Phyllis Canal is a prestressed concrete tee beam carrying SMA3613;MCMILLAN over Phyllis Canal in Ada County, Idaho. It was built in 1967, so it is 58 years old, older than the Idaho average of 45.3 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 1,300 vehicles a day, roughly 7% of them trucks, projected to reach 1,950 by 2042. The structure is 38 ft (11.6 m) long and 28 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesSMA3613;MCMILLAN
CrossesPhyllis Canal
Location3.0 S. 0.3 W. Star
RouteCounty Highway 3613
CountyAda County
StateIdaho
Coordinates43.64861, -116.4995
Functional classRural Minor 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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating52 US tons
Inventory rating31 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length38 ft (11.6 m)
Longest span37 ft (11.3 m)
Deck width28 ft (8.6 m)
Roadway width27 ft (8.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,300 (2023)
Projected traffic1,950 by 2042
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$594,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SMA3613;MCMILLAN over Phyllis Canal built?

It was built in 1967, making it 58 years old in 2025.

What condition is SMA3613;MCMILLAN over Phyllis Canal 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 March 2023.

How much traffic does SMA3613;MCMILLAN over Phyllis Canal carry?

About 1,300 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is SMA3613;MCMILLAN over Phyllis Canal?

The structure is 38 ft (11.6 m) long with a longest span of 37 ft (11.3 m) and a deck 28 ft wide.

Who owns SMA3613;MCMILLAN over Phyllis Canal?

It is owned by the County Highway Agency.