US Bridges

Mullan RD over Irrigation Canal

Poor

Missoula County, Montana · 6M SE Frenchtown · Structure no. S00263008+00001

Built
1970
55 years old
Condition
Poor
inspected February 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
23 ft
1 main span
Daily traffic
1,635
2023 count
Owner
State
State Highway Agency

About this bridge

Mullan RD over Irrigation Canal is a steel stringer/multi-beam or girder carrying Mullan RD over Irrigation Canal in Missoula County, Montana. It was built in 1970, so it is 55 years old, older than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 1,635 vehicles a day, roughly 1% of them trucks, projected to reach 1,717 by 2043. The structure is 23 ft (7 m) long and 28 ft wide. If it were closed, the detour would be 16.2 mi (26 km).

Location

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CarriesMullan RD
CrossesIrrigation Canal
Location6M SE Frenchtown
RouteState Highway 263
CountyMissoula County
StateMontana
Coordinates46.92644, -114.16695
Functional classRural Major Collector

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
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 rating63.1 US tons
Inventory rating48 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckCorrugated steel
Main spans1
Design loadUnknown
Structure length23 ft (7 m)
Longest span23 ft (7 m)
Deck width28 ft (8.5 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,635 (2023)
Projected traffic1,717 by 2043
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed16.2 mi (26 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$57,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Mullan RD over Irrigation Canal built?

It was built in 1970, making it 55 years old in 2025.

What condition is Mullan RD over Irrigation Canal in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in February 2024.

How much traffic does Mullan RD over Irrigation Canal carry?

About 1,635 vehicles per day (2023 count), of which roughly 1% are trucks.

How long is Mullan RD over Irrigation Canal?

The structure is 23 ft (7 m) long with a longest span of 23 ft (7 m) and a deck 28 ft wide.

Who owns Mullan RD over Irrigation Canal?

It is owned by the State Highway Agency.