US Bridges

SH 28 over Birch Creek

Fair

Clark County, Idaho · 2 N. Blue Dome · Structure no. 000000000013365

Built
1972
53 years old
Condition
Fair
inspected July 2023
Type
Frame
Concrete
Length
24 ft
1 main span
Daily traffic
680
2023 count
Owner
State
State Highway Agency

About this bridge

SH 28 over Birch Creek is a concrete frame carrying SH 28 over Birch Creek in Clark County, Idaho. It was built in 1972, so it is 53 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 680 vehicles a day, roughly 24% of them trucks, projected to reach 1,020 by 2042. The structure is 24 ft (7.3 m) long and 32 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesSH 28
CrossesBirch Creek
Location2 N. Blue Dome
RouteState Highway 28
CountyClark County
StateIdaho
Coordinates44.17647, -112.92878
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating72 US tons
Inventory rating43 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length24 ft (7.3 m)
Longest span24 ft (7.3 m)
Deck width32 ft (9.7 m)
Roadway width29 ft (8.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic680 (2023)
Projected traffic1,020 by 2042
Trucks24%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was SH 28 over Birch Creek built?

It was built in 1972, making it 53 years old in 2025.

What condition is SH 28 over Birch 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 July 2023.

How much traffic does SH 28 over Birch Creek carry?

About 680 vehicles per day (2023 count), of which roughly 24% are trucks.

How long is SH 28 over Birch Creek?

The structure is 24 ft (7.3 m) long with a longest span of 24 ft (7.3 m) and a deck 32 ft wide.

Who owns SH 28 over Birch Creek?

It is owned by the State Highway Agency.