National Bridge Inventory: Alaska



  • Of the 1,626 bridges in the state, 126, or 7.7 percent, are classified as structurally deficient. This means one of the key elements is in poor or worse condition.
  • This is down from 155 bridges classified as structurally deficient in 2018.
  • The deck area of structurally deficient bridges accounts for 6.9 percent of total deck area on all structures.
  • 9 of the structurally deficient bridges are on the Interstate Highway System. A total of 84.1 percent of the structurally deficient bridges are not on the National Highway System, which includes the Interstate and other key roads linking major airports, ports, rail and truck terminals.
  • 133 bridges are posted for load, which may restrict the size and weight of vehicles crossing the structure.
  • The state has identified needed repairs on 260 bridges at an estimated cost of $250.6 million.
  • This compares to 306 bridges that needed work in 2018.

County Year Built Daily Crossings Type of Bridge Location
Ketchikan Gateway 1955 14,046 Urban minor arterial South Tongass Hwy over Water St Viaduct
Fairbanks North Star 1988 13,700 Urban Interstate Parks Highway over Cushman St Uc
Ketchikan Gateway 1957 11,900 Urban minor arterial South Tongass Hwy over Hoadley Creek
Ketchikan Gateway 1975 5,250 Urban minor arterial North Tongass Hwy over Ward Creek
Anchorage 1966 5,080 Rural Interstate Seward Highway over Portage Creek No 1
Anchorage 1967 4,276 Rural Interstate Seward Highway over Twenty mile River
Fairbanks North Star 1953 4,130 Urban minor arterial Minnie Street over Noyes Slough (Minnie St)
Anchorage 1966 3,900 Rural Interstate Seward Highway over Placer River Main Cross
Anchorage 1967 3,900 Rural Interstate Seward Highway over Placer River overflow
Kenai Peninsula 1959 3,490 Rural arterial Sterling Highway over South Fork Anchor River
Matanuska-Susitna 1962 2,650 Rural Interstate Parks Highway over Sheep Creek
Fairbanks North Star 1960 2,600 Urban collector Aurora Drive over Noyes Slough (Aurora)
Kodiak Island 1980 2,530 Rural major collector Rezanof Drive over Sargent Creek
Ketchikan Gateway 1957 2,512 Urban local road Park/Harris St over Ketchikan Creek
Kodiak Island 1980 1,770 Rural major collector Rezanof Drive over Russian River
Kenai Peninsula 1965 1,700 Rural arterial Seward Highway over Snow River West Channel
Kenai Peninsula 1965 1,700 Rural arterial Seward Highway over Snow River Cntr Channel
Matanuska-Susitna 1961 1,580 Rural Interstate Glenn Highway over Kings River
Not Available 1985 1,200 Rural major collector Craig/Klawock/Holl over Crab Creek Culvert
Not Available 1954 1,110 Rural major collector Copper River Hwy over Eyak River
Not Available 1976 1,020 Rural major collector Gustavus Airport R over Salmon River
Not Available 1980 947 Rural arterial Marine Hwy Route over Skagway Ferry Terminal
Not Available 1974 880 Rural Interstate Richardson Highway over Gulkana River
Ketchikan Gateway 1952 820 Urban collector South Tongass Hwy over Herring Cove
Ketchikan Gateway 1920 720 Urban local road Water Street over Water St No 1 Trestle
Type of Bridge Number of Bridges Area of All Bridges
(sq. meters)
Daily Crossings on All Bridges Number of Structurally Deficient Bridges Area of Structurally Deficient Bridges
(sq. meters)
Daily Crossings on Structurally Deficient Bridges
Rural Interstate 163 163,787 504,400 8 9,894 22,446
Rural arterial 104 60,663 106,921 5 3,566 7,947
Rural minor arterial 72 31,638 65,790 5 1,172 1,160
Rural major collector 215 117,424 103,735 16 9,995 8,409
Rural minor collector 116 37,236 34,954 9 1,282 736
Rural local road 696 99,570 80,097 65 12,171 2,429
Urban Interstate 39 34,231 642,907 1 759 13,700
Urban freeway/expressway 0 0 0 0 0 0
Urban other principal arterial 66 103,920 833,626 0 0 0
Urban minor arterial 45 66,841 321,203 4 9,317 35,326
Urban collector 45 25,934 91,867 3 772 3,430
Urban local road 65 23,546 33,870 10 3,502 3,612
Total 1,626 764,791 2,819,370 126 52,431 99,195
Type of Work Number of Bridges Cost to Repair
(in millions)
Daily Crossings Area of Bridges
(sq. meters)
Bridge replacement 29 $30 356 5,597
Widening & rehabilitation 0 $0 0 0
Rehabilitation 106 $139 98,961 47,950
Deck rehabilitation/replacement 1 $0 10 69
Other structural work 124 $82 22,125 22,746
Total 260 $251 121,452 76,361

About the data:

Data and cost estimates are from the Federal Highway Administration (FHWA) National Bridge Inventory (NBI), downloaded on February 1, 2023. Note that specific conditions on bridges may have changed as a result of recent work or updated inspections.

Effective January 1, 2018, FHWA changed the definition of structurally deficient as part of the final rule on highway and bridge performance measures, published May 20, 2017 pursuant to the 2012 federal aid highway bill Moving Ahead for Progress in the 21st Century Act (MAP-21). Two measures that were previously used to classify bridges as structurally deficient are no longer used. This includes bridges where the overall structural evaluation was rated in poor or worse condition, or where the adequacy of waterway openings was insufficient.

The new definition limits the classification to bridges where one of the key structural elements—the deck, superstructure, substructure or culverts, are rated in poor or worse condition. During inspection, the conditions of a variety of bridge elements are rated on a scale of 0 (failed condition) to 9 (excellent condition). A rating of 4 is considered “poor” condition.

Cost estimates have been derived by ARTBA, based on 2021 average bridge replacement costs for structures on and off the National Highway System, published by FHWA. Bridge rehabilitation costs are estimated to be 68 percent of replacement costs. A bridge is considered to need repair if the structure has identified repairs as part of the NBI, a repair cost estimate is supplied by the bridge owner or the bridge is classified as structurally deficient. Please note that for a few states, the number of bridges needing to be repaired can vary significantly from year to year, and reflects the data entered by the state.

Bridges are classified by FHWA into types based on the functional classification of the roadway on the bridge. Interstates comprise routes officially designated by the Secretary of Transportation. Other principal arterials serve major centers of urban areas or provide mobility through rural areas. Freeways and expressways have directional lanes generally separated by a physical barrier, and access/egress points generally limited to on- and off-ramps. Minor arterials serve smaller areas and are used for trips of moderate length. Collectors funnel traffic from local roads to the arterial network; major collectors have higher speed limits and traffic volumes and are longer in length and spaced at greater intervals, while minor collectors are shorter and provide service to smaller communities. Local roads do not carry through traffic and are intended for short distance travel.

17
Compared to 17 in 2021

in the nation in % of structurally deficient bridges

1. West Virginia 20.0%
16. Nebraska 8.0%
17. Alaska 8.0%
18. New Hampshire 8.0%

45
Compared to 45 in 2021

in the nation in # of structurally deficient bridges

1. Iowa 4,604
44. Rhode Island 130
45. Alaska 126
46. Arizona 107

18
Compared to 17 in 2021

in the nation in % of structurally deficient bridge deck area

1. Rhode Island 17.0%
18. Alaska 7.0%
19. Montana 7.0%
Full State Ranking

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  • Source: Data is from the Federal Highway Administration (FHWA) National Bridge Inventory (NBI), downloaded on February 1, 2023. Note that specific conditions on bridges may have changed as a result of recent work or updated inspections.

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