Cypress Street Viaduct
Encyclopedia
The Cypress Street Viaduct, often referred to as the Cypress Structure, was a 1.6 mile long, raised two-tier, multi-lane (four lanes per deck) freeway constructed of reinforced concrete that was originally part of the Nimitz Freeway (State Highway 17, and later, Interstate 880) in Oakland, California
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...

.

It replaced an earlier single-deck viaduct constructed in the 1930s as one of the approaches to the San Francisco – Oakland Bay Bridge. It was located along Cypress Street between 7th Street and Interstate 80 in the West Oakland
West Oakland, Oakland, California
West Oakland is a neighborhood situated in the northwestern corner of Oakland, California along the waterfront near the Port of Oakland and San Francisco – Oakland Bay Bridge. It lies at an elevation of 13 feet .-History:...

 neighborhood.

It officially opened to traffic on June 11, 1957 and was in use until the Loma Prieta earthquake
Loma Prieta earthquake
The Loma Prieta earthquake, also known as the Quake of '89 and the World Series Earthquake, was a major earthquake that struck the San Francisco Bay Area of California on October 17, 1989, at 5:04 p.m. local time...

 occurred on October 17, 1989, when much of the upper tier collapsed onto the lower tier resulting in 42 fatalities.

Construction

The double-decked viaduct was initially designed in 1949 by the City of Oakland as a way to ease traffic on local streets leading to the Bay Bridge, such as Cypress Street (which was California State Route 17 at the time).

The southernmost portion of the Cypress Street viaduct, which was designed as a central offramp structure exiting at Market Street between Fifth and Sixth Streets to the Eighth Street/Seventh Street on/off ramps, was the first phase of the overall project completed in October, 1955 by contractors Frederickson and Watson at a cost of $1.7 million. Construction on the second phase of the project, the double-decked viaduct portion (which started from Adeline Street in the south to the Bay Bridge Distribution Structure
MacArthur Maze
The MacArthur Maze refers to the large freeway interchange located near the eastern end of the San Francisco – Oakland Bay Bridge in Oakland, California and is the largest freeway interchange in the world...

 in the north), began in February, 1956 by contractors Grove, Wilson, Shepard and Kruge at a cost of $8.3 million, bringing the total cost of the viaduct project to $10 million. It was touted as the first double-decked viaduct when it officially opened to traffic on June 11, 1957.

Loma Prieta earthquake

On October 17, 1989, the portion of the structure from 16th Street north all the way to the MacArthur Maze collapsed during the Loma Prieta earthquake
Loma Prieta earthquake
The Loma Prieta earthquake, also known as the Quake of '89 and the World Series Earthquake, was a major earthquake that struck the San Francisco Bay Area of California on October 17, 1989, at 5:04 p.m. local time...

, due to ground saturation and structural flaws.

When it was in use, the upper tier was used by southbound traffic, and the lower tier was used by northbound traffic. Some sections of the Cypress Street Viaduct were largely supported by two columns on either side, but some sections were only supported beneath by a single supporting column. The design was unable to survive the earthquake because the upper portions of the exterior columns were not tied by reinforcing to the lower columns, and the columns were not sufficiently ringed to prevent bursting. At the time of its design, such structures were not analyzed as a whole, and it appears that large structure motion contributed to the collapse. It was built on filled land, which is highly susceptible to soil liquefaction
Soil liquefaction
Soil liquefaction describes a phenomenon whereby a saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid....

 during an earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...

 and exhibits larger ground motion.

After the earth stopped moving, local residents and workers began crawling into and climbing upon the shattered structure with the goal of rescuing those left alive. Many were saved; some only by amputation of trapped limbs. The collapse of the upper tier onto the lower tier resulted in 42 fatalities—two-thirds of the total quake death toll of 63.

The viaduct was torn down, Cypress Street was renamed (now known as Mandela Parkway, in honor of Nelson Mandela
Nelson Mandela
Nelson Rolihlahla Mandela served as President of South Africa from 1994 to 1999, and was the first South African president to be elected in a fully representative democratic election. Before his presidency, Mandela was an anti-apartheid activist, and the leader of Umkhonto we Sizwe, the armed wing...

) with a landscaped median planted where the viaduct once stood. Before reconstruction occurred, the viaduct ended at the Eighth Street exit on the southern end, with the two roadways going over Seventh Street, while the southbound exit off the MacArthur Maze onto Cypress Street at 32nd Street remained open to local traffic on the northern end.

Reconstruction around West Oakland

In 1997, the Nimitz Freeway was rerouted to loop around the area using a largely ground-level design with more conventional single-level viaduct. The space was mainly taken from a railroad yard which was relocated. The exit at Eighth Street was eliminated, a southbound exit near Seventh and Union Street and a single northbound and southbound exit at Seventh Street, near the Port of Oakland was constructed also providing access via a frontage road to Grand Avenue and the Oakland Army Base, before a viaduct-type interchange splitting traffic to the Bay Bridge via Grand Avenue and also northbound to the Eastshore Freeway.

During construction of the new section of the Nimitz Freeway, a team of archaeologists made many interesting discoveries about the people who lived in West Oakland in the 19th century.

Due to cost overruns, the costs of the replacement freeway doubled from initial estimates of $650 million to $1.25 billion ($250 million per mile) making the five-mile freeway replacement the most expensive project in the state's history at the time. (It would be subsequently overshadowed by the northbound addition of the Benicia Bridge and the Eastern span replacement of the San Francisco-Oakland Bay Bridge
Eastern span replacement of the San Francisco-Oakland Bay Bridge
The eastern span replacement of the San Francisco – Oakland Bay Bridge has been under construction since 2002. Originally scheduled to open in 2007, it is now scheduled to open to traffic in 2013 at an estimated cost of $6.3 billion....

.) The cost overruns were mainly due to the
opposition to replacing the highway on the site of the one partially destroyed in 1989, having to purchase land and property from Southern Pacific Railroad
Southern Pacific Railroad
The Southern Pacific Transportation Company , earlier Southern Pacific Railroad and Southern Pacific Company, and usually simply called the Southern Pacific or Espee, was an American railroad....

 and Amtrak
Amtrak
The National Railroad Passenger Corporation, doing business as Amtrak , is a government-owned corporation that was organized on May 1, 1971, to provide intercity passenger train service in the United States. "Amtrak" is a portmanteau of the words "America" and "track". It is headquartered at Union...

 (moving part of the rail yard, and causing the earthquake-damaged 16th Street Amtrak Station to be closed and replaced with two Amtrak stations in Jack London Square
Oakland – Jack London Square (Amtrak station)
Oakland is an Amtrak station located in downtown Oakland, California. Opened in 1994, the building is located at 245 Second Street in Oakland, it is served by the Capitol Corridor, Coast Starlight, and San Joaquins trains...

 and Emeryville
Emeryville (Amtrak station)
The Emeryville Amtrak station is an Amtrak station in Emeryville, California that replaced the older Amtrak 16th Street Station in Oakland. The original Beaux-Arts Oakland 16th Street Station was declared unsafe due to unreinforced masonry after sustaining damage in the Loma Prieta Earthquake of...

), the United States Postal Service
United States Postal Service
The United States Postal Service is an independent agency of the United States government responsible for providing postal service in the United States...

 (having to replace a parking lot with a parking garage), also replacing BART support beams and purchasing land from the U.S. Army (the freeway went through the Oakland Army Base
Oakland Army Base
The Oakland Army Base, also known as the Oakland Army Terminal, was a former United States Army base in the San Francisco Bay Area of California...

 to re-route the freeway).

Exit list

The following is an exit list of the former Cypress Viaduct/Nimitz Freeway prior to the Loma Prieta earthquake
Loma Prieta earthquake
The Loma Prieta earthquake, also known as the Quake of '89 and the World Series Earthquake, was a major earthquake that struck the San Francisco Bay Area of California on October 17, 1989, at 5:04 p.m. local time...

 and subsequent demolition.

The entire route was in Oakland.
Interchange Notes
Southern End of Viaduct ' onMouseout='HidePop("73922")' href="/topics/San_Jose,_California">San Jose
San Jose, California
San Jose is the third-largest city in California, the tenth-largest in the U.S., and the county seat of Santa Clara County which is located at the southern end of San Francisco Bay...

)
Market Street, Harbor Terminal
Port of Oakland
The Port of Oakland was the first major port on the Pacific Coast of the United States to build terminals for container ships. It is now the fifth busiest container port in the United States, behind Long Beach, Los Angeles, Newark, and Savannah...

Southbound and Northbound exit and entrance
8th Street, Cypress Street Northbound exit
7th Street at Kirkham Street Southbound entrance
14th Street, Downtown Oakland
Downtown Oakland
Downtown Oakland is the central business district of Oakland, California; roughly bounded by 6th Street or the Oakland Estuary on the southwest, Interstate 980 on the northwest, Grand Avenue on the northeast, and Lake Merritt on the east....

Northbound entrance and Southbound exit
Cypress Street, Peralta Street Southbound exit
Cypress Street at 32nd Street Northbound entrance
Northbound exit and Southbound Entrance
Northbound/Westbound exit and Southbound/Eastbound Entrance
Northern End of Viaduct (//, The MacArthur Maze)

Similar structures damaged by earthquakes

  • Alaskan Way Viaduct
    Alaskan Way Viaduct
    The Alaskan Way Viaduct, completed on April 4, 1953, is a double-decked elevated section of State Route 99 that runs along the Elliott Bay waterfront in Seattle's Industrial District and downtown Seattle. It is the smaller of the two major north–south traffic corridors through Seattle ,...

     (not destroyed)
  • Central Freeway
    Central Freeway
    The Central Freeway is a roughly one-mile elevated freeway in San Francisco, California, United States, connecting the Bayshore/James Lick Freeway with the Hayes Valley neighborhood. Most of the freeway is part of US 101, which exits at Mission Street on the way to the Golden Gate Bridge...

  • Embarcadero Freeway
  • Hanshin Expressway
    Hanshin Expressway
    The is a network of expressways surrounding Osaka, Kobe and Kyoto, Japan. Operated by , it opened in 1962.Portions of the Hanshin Expressway collapsed during the Kobe earthquake on January 17, 1995. These sections were rebuilt by 1996...


External links

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