Juneau-Douglas Bridge
Encyclopedia
The Juneau-Douglas Bridge (formally the Douglas Bridge; also colloquially the J. D. Bridge) is located in Juneau, Alaska
. Spanning the Gastineau Channel
, it connects Juneau's eastern, mainland side with the cities community located on Douglas Island
to the west. The current span is the second bridge to bear the same name; the original one, built in 1935, was demolished in 1981 following the completion of the replacement bridge in 1980.
The bridge is the only roadway link to Douglas Island and its communities: Douglas
, North Douglas and West Juneau
, the latter of which is situated at the bridge's western terminus. Egan Drive
, Juneau's principal arterial highway, and the bridge are connected at the intersection of Egan and 10th Street, one of the busiest intersections in Southeast Alaska
. The current bridge provides a two lane road that accommodates vehicular and pedestrian traffic, as well as a bike path.
The 1935 bridge, of cantilever
steel truss
design, underwent construction from both sides of the channel.
The Civil Works Administration
and the Public Works Administration
provided grants and loans to assist with construction costs. Its opening was celebrated on October 13, 1935. In 1975, construction began on a new girder bridge
and it was completed in 1980. The following year, the old bridge was demolished. For a time, the two bridges stood side by side.
A 2006 Alaska Department of Transportation & Public Facilities
project included some bridge joint and pavement improvements, as well as a recommendation to add a reversible center lane. Seeking a solution to relieve traffic on the existing bridge, the CBJ has identified a need for a North Douglas Crossing of the channel as a top transportation priority for Juneau.
. It measures 20.2 metres (66.3 ft) in width, and has a span of 189 metres (620.1 ft).
zone" on its north side.
Juneau, Alaska
The City and Borough of Juneau is a unified municipality located on the Gastineau Channel in the panhandle of the U.S. state of Alaska. It has been the capital of Alaska since 1906, when the government of the then-District of Alaska was moved from Sitka as dictated by the U.S. Congress in 1900...
. Spanning the Gastineau Channel
Gastineau Channel
Gastineau Channel is a channel between the mainland of the U.S. state of Alaska and Douglas Island in the Alexander Archipelago of southeastern Alaska. It separates Juneau on the mainland side from Douglas , on Douglas Island. The first European to sight the channel was Joseph Whidbey early in...
, it connects Juneau's eastern, mainland side with the cities community located on Douglas Island
Douglas Island
Douglas Island is a tidal island in the U.S. state of Alaska, just west of downtown Juneau and east of Admiralty Island. It is separated from mainland Juneau by the Gastineau Channel. The Juneau-Douglas Bridge, connecting the island with Juneau, provides a two lane road to and from the island and...
to the west. The current span is the second bridge to bear the same name; the original one, built in 1935, was demolished in 1981 following the completion of the replacement bridge in 1980.
The bridge is the only roadway link to Douglas Island and its communities: Douglas
Douglas, Alaska
Douglas, Alaska is an area on Douglas Island in southeastern Alaska. Itoriginated in 1881 as a place providing services to miners of the nearby Treadwell gold mine, and was incorporated as a city in 1902. Douglas was once a larger town than neighboring Juneau, but dwindled in the early 1900s as...
, North Douglas and West Juneau
West Juneau, Alaska
West Juneau is a populated place in Juneau, Alaska, United States. It is located on Douglas Island northwest of Douglas. The name was first published by the United States Geological Survey in 1948 and entered into the Geographic Names Information System on March 31, 1981...
, the latter of which is situated at the bridge's western terminus. Egan Drive
Alaska Route 7
Alaska Route 7 is a state highway in the Alaska Panhandle of the U.S. state of Alaska. It consists of four unconnected pieces, serving some of the Panhandle communities that the Alaska Marine Highway ferries stop at, and connecting to the Alaska Highway in Yukon via the Haines Highway.-Route...
, Juneau's principal arterial highway, and the bridge are connected at the intersection of Egan and 10th Street, one of the busiest intersections in Southeast Alaska
Alaska Panhandle
Southeast Alaska, sometimes referred to as the Alaska Panhandle, is the southeastern portion of the U.S. state of Alaska, which lies west of the northern half of the Canadian province of British Columbia. The majority of Southeast Alaska's area is part of the Tongass National Forest, the United...
. The current bridge provides a two lane road that accommodates vehicular and pedestrian traffic, as well as a bike path.
History
Though strong currents occur at times under the bridge, prior to construction of the original bridge, residents of Douglas Island would row across the channel to reach the mainland.The 1935 bridge, of cantilever
Cantilever
A cantilever is a beam anchored at only one end. The beam carries the load to the support where it is resisted by moment and shear stress. Cantilever construction allows for overhanging structures without external bracing. Cantilevers can also be constructed with trusses or slabs.This is in...
steel truss
Truss
In architecture and structural engineering, a truss is a structure comprising one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. External forces and reactions to those forces are considered to act only at the nodes and result in...
design, underwent construction from both sides of the channel.
The Civil Works Administration
Civil Works Administration
The Civil Works Administration was established by the New Deal during the Great Depression to create manual labor jobs for millions of unemployed. The jobs were merely temporary, for the duration of the hard winter. Harry L. Hopkins was put in charge of the organization. President Franklin D...
and the Public Works Administration
Public Works Administration
The Public Works Administration , part of the New Deal of 1933, was a large-scale public works construction agency in the United States headed by Secretary of the Interior Harold L. Ickes. It was created by the National Industrial Recovery Act in June 1933 in response to the Great Depression...
provided grants and loans to assist with construction costs. Its opening was celebrated on October 13, 1935. In 1975, construction began on a new girder bridge
Girder bridge
A girder bridge, in general, is a bridge built of girders placed on bridge abutments and foundation piers. In turn, a bridge deck is built on top of the girders in order to carry traffic. There are several different subtypes of girder bridges:...
and it was completed in 1980. The following year, the old bridge was demolished. For a time, the two bridges stood side by side.
A 2006 Alaska Department of Transportation & Public Facilities
Alaska Department of Transportation & Public Facilities
The Alaska Department of Transportation & Public Facilities is a department within the government of Alaska. The Department of Transportation & Public Facilities provides for the safe movement of people and goods and the delivery of State services. It has its headquarters in Juneau.-External links:*...
project included some bridge joint and pavement improvements, as well as a recommendation to add a reversible center lane. Seeking a solution to relieve traffic on the existing bridge, the CBJ has identified a need for a North Douglas Crossing of the channel as a top transportation priority for Juneau.
Structure
The deck of the newer bridge was constructed using prestressed concretePrestressed concrete
Prestressed concrete is a method for overcoming concrete's natural weakness in tension. It can be used to produce beams, floors or bridges with a longer span than is practical with ordinary reinforced concrete...
. It measures 20.2 metres (66.3 ft) in width, and has a span of 189 metres (620.1 ft).
Waterway
At 0 foot (0 m) tide, the Juneau-Douglas Bridge is 66.4 feet (20.2 m) above the waterline. A spring Dolly Varden fishery is situated directly beneath the bridge. The bridge forms a "no wakeWake
A wake is the region of recirculating flow immediately behind a moving or stationary solid body, caused by the flow of surrounding fluid around the body.-Fluid dynamics:...
zone" on its north side.