US Bridges

Bostwick Lake Road over Bostwick No. 1

Fair

Ketchikan Gateway Borough, Alaska · Mile Point 1.2 · Structure no. 2346

Built
2006
19 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
40 ft
1 main span
Daily traffic
10
2018 count
Owner
State
State Park, Forest, or Reservation Agency

About this bridge

Bostwick Lake Road over Bostwick No. 1 is a steel stringer/multi-beam or girder carrying Bostwick Lake Road over Bostwick No. 1 in Ketchikan Gateway Borough, Alaska. It was built in 2006, so it is 19 years old, younger than the Alaska average of 35.9 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 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 10 vehicles a day, roughly 70% of them trucks, projected to reach 15 by 2035. The structure is 40 ft (12.2 m) long and 18 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

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CarriesBostwick Lake Road
CrossesBostwick No. 1
LocationMile Point 1.2
RouteState Lands Road 0
CountyKetchikan Gateway Borough
StateAlaska
Coordinates55.34115, -131.74295
Functional classUrban Local

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating70.1 US tons
Inventory rating43 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans1
Design loadHS 20
Structure length40 ft (12.2 m)
Longest span40 ft (12.1 m)
Deck width18 ft (5.5 m)
Roadway width16 ft (4.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10 (2018)
Projected traffic15 by 2035
Trucks70%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Park, Forest, or Reservation Agency
Maintained byState Park, Forest, or Reservation 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 Bostwick Lake Road over Bostwick No. 1 built?

It was built in 2006, making it 19 years old in 2025.

What condition is Bostwick Lake Road over Bostwick No. 1 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 June 2023.

How much traffic does Bostwick Lake Road over Bostwick No. 1 carry?

About 10 vehicles per day (2018 count), of which roughly 70% are trucks.

How long is Bostwick Lake Road over Bostwick No. 1?

The structure is 40 ft (12.2 m) long with a longest span of 40 ft (12.1 m) and a deck 18 ft wide.

Who owns Bostwick Lake Road over Bostwick No. 1?

It is owned by the State Park, Forest, or Reservation Agency.