Posey and Webster Street Tubes
Encyclopedia
Oakland, California
Oakland is a major West Coast port city on San Francisco Bay in the U.S. state of California. It is the eighth-largest city in the state with a 2010 population of 390,724...
and Alameda, California
Alameda, California
Alameda is a city in Alameda County, California, United States. It is located on Alameda Island and Bay Farm Island, and is adjacent to Oakland in the San Francisco Bay. The Bay Farm Island portion of the city is adjacent to the Oakland International Airport. At the 2010 census, the city had a...
, running beneath the Alameda-Oakland Estuary
Oakland Estuary
The Oakland Estuary is the body of water separating the cities of Oakland and Alameda, California, in the San Francisco Bay Area. On its western end it connects to San Francisco Bay, while its eastern end connects to San Leandro Bay.-Crossings:...
. 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
Holland Tunnel
The Holland Tunnel is a highway tunnel under the Hudson River connecting the island of Manhattan in New York City with Jersey City, New Jersey at Interstate 78 on the mainland. Unusual for an American public works project, it is not named for a government official, politician, or local hero or...
.
Construction
The Posey Tube, an Immersed tubeImmersed tube
An immersed tube is a kind of underwater tunnel composed of segments, constructed elsewhere and floated to the tunnel site to be sunk into place and then linked together. They are commonly used for road and rail crossings of rivers, estuaries and sea channels/harbours...
completed and opened to traffic on October 27, 1928, was named after George Posey, Alameda County
Alameda County, California
Alameda County is a county in the U.S. state of California. It occupies most of the East Bay region of the San Francisco Bay Area. As of the 2010 census it had a population of 1,510,271, making it the 7th most populous county in the state...
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 tube
Immersed tube
An immersed tube is a kind of underwater tunnel composed of segments, constructed elsewhere and floated to the tunnel site to be sunk into place and then linked together. They are commonly used for road and rail crossings of rivers, estuaries and sea channels/harbours...
s, constructed by sinking precast concrete
Precast concrete
By producing precast concrete in a controlled environment , the precast concrete is afforded the opportunity to properly cure and be closely monitored by plant employees. Utilizing a Precast Concrete system offers many potential advantages over site casting of concrete...
segments to a trench in the Estuary floor, then sealing them together to create a tunnel. The Posey Tube replaced a swing bridge that interfered with maritime traffic. The ventilation buildings that house the exhaust and fresh air fans are built in an art deco style.
The ventilation of toxic vehicular exhaust fume design was modeled on that of the Holland Tunnel
Holland Tunnel
The Holland Tunnel is a highway tunnel under the Hudson River connecting the island of Manhattan in New York City with Jersey City, New Jersey at Interstate 78 on the mainland. Unusual for an American public works project, it is not named for a government official, politician, or local hero or...
's ventilation system, and Ole Singstad
Ole Singstad
Ole Knutsen Singstad was a Norwegian-American civil engineer who innovated the ventilation system for the Holland Tunnel and advanced the use of the "Sunk-tube" method of underwater vehicular tunnel building, a system of constructing the tunnels with prefabricated sections.By 1950...
(who had designed the pioneering ventilation system of the Holland Tunnel) consulted.