Bay Bridge

Le pont San Francisco–Oakland (en anglais : San Francisco–Oakland Bay Bridge), plus connu sous le nom de Bay Bridge, est constitué de deux ponts traversant la baie de San Francisco en Californie, aux États-Unis. Il relie les villes de San Francisco à l'ouest et Oakland à l'est et s'appuie au milieu sur Yerba Buena Island. Faisant partie de l'itinéraire de l'Interstate 80 et constituant un lien direct entre les villes de San Francisco et Oakland, son trafic est d'environ 280 000 véhicules par jour sur ses deux niveaux. C'est l'un des plus longs ponts suspendus au monde. Il apparaît par ailleurs dans le jeu vidéo Grand Theft Auto: San Andreas sous le nom de Garver Bridge.

1. Caractéristiques

Le pont se compose de deux segments principaux reliant une île centrale, l'île de Yerba Buena, à chaque rivage. Le segment occidental se terminant à San Francisco se compose de deux ponts suspendus avec un ancrage central. L'envergure orientale se terminant à Oakland se compose d'une chaussée de botte, de cinq ponts de botte de milieu-envergure et d'une envergure en porte-à-faux de double-tour, remplacée depuis 2013 par une structure entièrement nouvelle[pas clair]. Le Bay Bridge est la passerelle d'acier la plus longue du monde 7 200 m de long et comprenant cinq couloirs de circulation. Il a exigé une telle quantité d'acier que, tressé en un seul câble, il relierait la Terre à la Lune, aller et retour[réf. nécessaire].

1. Conception

Les ponts originaux ont été conçus par Ralph Modjeski. Le pont de compartiment[Quoi ?] a été ouvert au trafic le 12 novembre 1936, six mois avant l'autre pont célèbre de San Francisco, le Golden Gate Bridge. Le poste de péage du côté d'Oakland (pour le trafic vers l'ouest) est suivi d'un ensemble de signaux lumineux régulés. Deux passages exclusivement dédiés aux autobus évitent les péages et les voies régulées par signaux lumineux. Il n'y a aucun signal lumineux régulé pour le trafic allant vers l'est, cependant le nombre de voies dans l'approche de San Francisco est structurellement limité, créant des protections dans cette direction pendant l'heure de pointe de soirée. Le pont est limité au trafic autoroutier : il n'est pas autorisé aux piétons, aux cyclistes et aux autres véhicules interdits sur autoroute. Cependant, les cyclistes peuvent entrer en contact avec CalTrans pour une traversée gratuite en camion. En octobre 2009, un ingénieur a découvert une faille dans l'une des structures métalliques du pont. Une solution fut d'insérer une pièce métallique pour soulager l'effort fourni par l'extrémité d'une pièce métallique.[pas clair] Cette solution, rapidement conçue, n'a pas résisté. Une deuxième pièce fut ajoutée. À la fin d'octobre 2009, elle semble accomplir la tâche prévue.

Compte tenu des risques importants d'effondrement en cas de tremblement de terre, la section Yerbas Buenas - Oakland est en cours de reconstruction (en). L'ancien pont sera détruit.

1. Chemin de fer

À l'origine, les voies de circulation pour automobiles se trouvaient toutes sur l'étage supérieur. On trouvait à l'étage inférieur trois voies pour camions et deux voies ferrées. Trois compagnies ferroviaires se partageaient la voie : la Southern Pacific (East Bay Electric Lines), les tramways interurbains du Key System ainsi que le Sacramento Northern Railway. L'alimentation électrique se faisait par caténaire (Southern Pacific) et troisième rail (Key System et Sacramento Northern). L'exploitation ferroviaire débuta le 23 septembre 1938. Dès 1941 déjà, seuls les tramways du Key System circulaient sur le Bay Bridge, jusqu'en avril 1958, date à laquelle tout service ferroviaire fut supprimé sur le pont et les voies démontées.

1. Nouveau pont Bay Bridge Eastern 2013

À la suite du séisme de Loma Prieta de 1989 avec l'effondrement d'une passerelle du côté est, le projet est de reconstruire un nouveau pont parasismique à côté de l'ancien. Le projet est estimé à 6,4 milliards de dollars. Il s'agit d'un pont suspendu d'un type particulier, empruntant aux ponts à haubans leurs suspentes inclinées de façon à ne pas avoir besoin de massifs d'ancrage. Les travaux ont commencé en 2002, avec cette fois-ci une 2 x 5 voies l'une à côté de l'autre et plus sur deux étages. Après 11 ans de travaux (1460 jours), le 2 septembre 2013, le pont est ouvert à la circulation et à la population.

Le démantèlement du vieux pont cantilever, dont la portée de 427 mètres était la 8e au monde pour le type de construction, débute en 2014.

1. Notes et références


1. Voir aussi


1. = Articles connexes =

Liste des ponts suspendus les plus longs Marée noire du Cosco Busan (impact avec le pont) Pont suspendu Pont suspendu auto-ancré

1. = Liens externes =

Ressources relatives à l'architecture : Office of Historic Preservation Registre national des lieux historiques Structurae

1. = Bibliographie =

Portail des ponts Portail du Registre national des lieux historiques Portail des routes Portail de l’océan Pacifique Portail des records Portail de San Francisco Portail d'Oakland

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Cosco Busan oil spill

The Cosco Busan oil spill occurred at 08:30 UTC-8 on 7 November 2007 between San Francisco and Oakland, California, in which 53,569 US gal (202,780 L) of IFO-380 heavy fuel oil, sometimes referred to as "bunker fuel", spilled into San Francisco Bay after the container ship Cosco Busan, operated by Fleet Management Limited struck Delta Tower of the San Francisco–Oakland Bay Bridge in thick fog. Investigators found that maritime pilot John Cota was impaired because of his use of prescription pharmaceuticals while piloting the container vessel, which rendered him unable to use the onboard radar and electronic navigation charts correctly. This occurred despite the fact that the Vessel Traffic Service of the United States Coast Guard warned Cota that the vessel was headed for the bridge. Cota was sentenced to 10 months in federal prison for his role in the incident. California Governor Arnold Schwarzenegger declared a state of emergency after meeting federal, state and local officials overseeing the cleanup. The proclamation made additional state personnel, funding and equipment available to assess and clean up the environmental damage.

Landmark

San Francisco Bay Area

The San Francisco Bay Area, commonly known as the Bay Area, is a region of California surrounding and including San Francisco Bay, and anchored by the cities of Oakland, San Francisco, and San Jose. The Association of Bay Area Governments defines the Bay Area as including the nine counties that border the estuaries of San Francisco Bay, San Pablo Bay, and Suisun Bay: Alameda, Contra Costa, Marin, Napa, San Mateo, Santa Clara, Solano, Sonoma, and San Francisco. Other definitions may be either smaller or larger, and may include neighboring counties which are not officially part of the San Francisco Bay Area, such as the Central Coast counties of Santa Cruz, San Benito, and Monterey, or the Central Valley counties of San Joaquin, Merced, and Stanislaus. The Bay Area is known for its natural beauty, prominent universities, technology companies, and affluence. The Bay Area contains many cities, towns, airports, and associated regional, state, and national parks, connected by a complex multimodal transportation network. The earliest archaeological evidence of human settlements in the Bay Area dates back to 8000–10,000 BC. The oral tradition of the Ohlone and Miwok people suggests they have been living in the Bay Area for several hundreds if not thousands of years. The Spanish empire claimed the area beginning in the early period of Spanish colonization of the Americas. The earliest Spanish exploration of the Bay Area took place in 1769. The Mexican government controlled the area from 1821 until the 1848 Treaty of Guadalupe Hidalgo. Also in 1848, James W. Marshall discovered gold in nearby mountains, resulting in explosive immigration to the area and the precipitous decline of the Native population. The California gold rush brought rapid growth to San Francisco. California was admitted as the 31st state in 1850. A major earthquake and fire leveled much of San Francisco in 1906. During World War II, the Bay Area played a major role in America's war effort in the Asiatic-Pacific Theater, with the San Francisco Port of Embarkation, of which Fort Mason was one of 14 installations and location of the headquarters, acting as a primary embarkation point for American forces. Since then, the Bay Area has experienced numerous political, cultural, and artistic movements, developing unique local genres in music and art and establishing itself as a hotbed of progressive politics. The postwar Bay Area saw large growth in the financial and technology industries, creating an economy with a gross domestic product of over $700 billion. In 2018 it was home to the third-highest concentration of Fortune 500 companies in the United States. The Bay Area is home to approximately 7.52 million people. The larger federal classification, the combined statistical area of the region which includes thirteen counties, is the second-largest in California—after the Greater Los Angeles area—and the fifth-largest in the United States, with over nine million people. The Bay Area's population is ethnically diverse: roughly three-fifths of the region's residents are Hispanic/Latino, Asian, African/Black, or Pacific Islander, all of whom have a significant presence throughout the region. Most of the remaining two-fifths of the population is non-Hispanic White American. The most populous cities of the Bay Area are Oakland, San Francisco, and San Jose, the latter of which had a population of 969,655 in 2023, making San Jose the area's largest city and the 13th-most populous in the United States. The San Francisco Bay Area's population has the third-oldest median age, following two Florida metros; and it is the fastest-aging of any metropolitan area in the U.S., described as a demographic "doom loop". Despite its urban character, San Francisco Bay is one of California's most ecologically sensitive habitats, providing important ecosystem services such as filtering the pollutants and sediments from rivers and supporting a number of endangered species. In addition, the Bay Area is known for its stands of coast redwoods, many of which are protected in state and county parks. The region is additionally known for the complexity of its landforms, the result of millions of years of tectonic plate movements. Because the Bay Area is crossed by six major earthquake faults, the region is particularly exposed to hazards presented by large earthquakes. The climate is temperate and conducive to outdoor recreational and athletic activities such as hiking, running, and cycling. The Bay Area is host to teams in each of the five largest North American men's professional sports leagues and is a cultural center for music, theater, and the arts. It is also host to numerous higher education institutions, including research universities such as the University of California, Berkeley, and Stanford University, the latter known for helping to create the high tech center called Silicon Valley. Home to 101 municipalities and 9 counties, governance in the Bay Area involves numerous local and regional jurisdictions, often with broad and overlapping responsibilities.

Neighbourhood Park

The Bay Lights

The Bay Lights was a site-specific monumental light sculpture and generative art installation on the western span of the San Francisco–Oakland Bay Bridge, designed to commemorate the 75th anniversary of its opening. The installation by light artist Leo Villareal included 25,000 individual white LEDs along 1.8 miles (2.9 km) of the cables on the north side of the suspension span of the bridge between Yerba Buena Island and San Francisco. The installation was controlled via a computer and displayed changing patterns that were not meant to repeat. The opening ceremony was held on March 5, 2013. Initially intended as a temporary installation, which ended on March 5, 2015, the project was re-installed as a longstanding feature of the Bay Bridge with permanent fixtures that were re-lit on January 30, 2016. After an extended run, the lights were turned off on March 5, 2023. An $11M fundraising effort is underway to return the lights in March 2025.

Art Landmark

Point of Infinity

Point of Infinity is a 69-foot-tall stainless steel sculpture by Japanese artist Hiroshi Sugimoto, installed on a Yerba Buena Island hilltop in San Francisco, California. The artwork also acts as a sundial. Installed in 2023, it is the first permanent sculpture commissioned for the Treasure Island Arts Program, and the artist's first major installation in the United States.

Art Landmark

Yerba Buena Tunnel

The Yerba Buena Tunnel, also known as the Yerba Buena Island Tunnel, is a highway tunnel in San Francisco, California. It is the part of San Francisco–Oakland Bay Bridge complex that crosses Yerba Buena Island. The Yerba Buena Tunnel carries ten lanes of Interstate 80 (I-80) on two decks, connecting the two component spans of the Bay Bridge, the western suspension span and the eastern self-anchored suspension span. At the opening of the Bay Bridge in 1936, it was the world's largest-bore tunnel.

Bridge Landmark