Posey and Webster Street Tubes

Infobox_Bridge
bridge_name=Posey Tube


caption=
official_name=
carries=2 lanes of SR 260 Northbound
(Signed as SR 61)
crosses=Oakland Estuary
locale=Alameda, California and Oakland, California
maint=California Department of Transportation
id=
design=
mainspan=
length=
width=
clearance=
below=
traffic=
open=October 27, 1928
closed=
toll=
map_cue=
map_

map_text=
map_width=
coordinates= coord|37|47|16|N|122|16|38|W|region:US_type:landmark
lat=
long=Infobox_Bridge
bridge_name=Webster Street Tube


caption=
official_name=
carries=2 lanes of SR 260 Southbound
(Signed as SR 61)
crosses=Oakland Estuary
locale=Alameda, California and Oakland, California
maint=California Department of Transportation
id=
design=
mainspan=
length=
width=
clearance=
below=
traffic=
open=1963The Posey Tube and the Webster Street Tube are two parallel underwater tunnels connecting the cities of Oakland and Alameda, California, running beneath the Alameda-Oakland Estuary. Currently, the Posey Tube carries Oakland-bound traffic under the Estuary, while the Webster Tube carries traffic bound for Alameda.

The Posey Tube is the second-oldest underwater vehicular tunnel in the US, preceded only by the Holland Tunnel.

Construction

The Posey Tube, completed and opened to traffic on October 27, 1928, was named after George Posey, Alameda County Surveyor during the tunnel's planning and construction, and also chief engineer on the construction project. The Webster Street Tube opened in 1963 to deal with the increased traffic between Oakland and Alameda. Both are immersed tubes, constructed by sinking precast concrete segments to a trench in the Estuary floor, then sealing them together to create a tunnel.

The design was modeled on that of the Holland Tunnel, and Ole Singstad (who had designed the pioneering ventilation system of the Holland Tunnel) consulted. [http://archiver.rootsweb.ancestry.com/th/read/NORWAY/2003-05/1051983030 Saga in Steel and Concrete, pp. 191–202] ]

Notes

References

* [http://www.alamedainfo.com/Posey_Tube.htm Posey Tube and Webster St Tube at AlamedaInfo.com by Gary Lenhart] (includes detailed timeline and historical photographs)
* citation
title=Saga in Steel and Concrete: Norwegian Engineers in America
last=Bjork
first=Kenneth
pub=Norwegian-American Historical Association
year=1947
url=http://www.naha.stolaf.edu/

Crossings navbox
structure = Crossings
place = Oakland Estuary
bridge = Posey and Webster Street Tubes
bridge signs =
upstream text = South
upstream = Park Street Bridge
downstream text = North
downstream = None