US Bridges

Iron Mountain RD over Rock Creek

Fair

Shasta County, California · 5.6 MI N of State Rt 299 · Structure no. 06C0022

Built
1931
94 years old, rebuilt 1970
Condition
Fair
inspected August 2024
Type
Slab
Concrete Continuous
Length
185 ft
8 main spans
Daily traffic
817
2012 count
Owner
County
County Highway Agency

About this bridge

Iron Mountain RD over Rock Creek is a concrete continuous slab carrying Iron Mountain RD over Rock Creek in Shasta County, California. It was built in 1931 and reconstructed in 1970, so it is 94 years old, older than the California average of 54.8 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 817 vehicles a day, roughly 10% of them trucks, projected to reach 982 by 2044. The structure is 185 ft (56.4 m) long and 25 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

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CarriesIron Mountain RD
CrossesRock Creek
Location5.6 MI N of State Rt 299
RouteCounty Highway 0
CountyShasta County
StateCalifornia
Coordinates40.61322, -122.45983
Functional classRural Minor Collector

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating62.5 US tons
Inventory rating37.5 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans8
Design loadHS 20
Structure length185 ft (56.4 m)
Longest span23 ft (7 m)
Deck width25 ft (7.5 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic817 (2012)
Projected traffic982 by 2044
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Iron Mountain RD over Rock Creek built?

It was built in 1931, making it 94 years old in 2025. It was reconstructed in 1970.

What condition is Iron Mountain RD over Rock Creek 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 August 2024.

How much traffic does Iron Mountain RD over Rock Creek carry?

About 817 vehicles per day (2012 count), of which roughly 10% are trucks.

How long is Iron Mountain RD over Rock Creek?

The structure is 185 ft (56.4 m) long with a longest span of 23 ft (7 m) and a deck 25 ft wide.

Who owns Iron Mountain RD over Rock Creek?

It is owned by the County Highway Agency.