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67-752: The first project of the Authority was the construction of the San Francisco–Oakland Bay Bridge . On September 16, 1940, the Authority purchased two private toll bridges, the Carquinez Bridge and the Antioch Bridge . On December 29, 1947, Director of Public Works Charles H. Purcell created the Division of San Francisco Bay Toll Crossings to carry out the planning, construction, and operations of all state-owned toll bridges. On September 12, 1951,

134-423: A balanced cantilever ; when they attach to a solid foundation, the counterbalancing arms are called anchor arms . Thus, in a bridge built on two foundation piers, there are four cantilever arms: two which span the obstacle, and two anchor arms that extend away from the obstacle. Because of the need for more strength at the balanced cantilever's supports, the bridge superstructure often takes the form of towers above

201-503: A bridge had a widespread public and political appeal. Yet the task was too much of an engineering and economic challenge, since the bay was too wide and too deep there. In 1921, more than forty years after Norton's death, an underground tube was considered, but it became clear that one would be inadequate for vehicular traffic. Support for a trans-bay crossing increased in the 1920s based on the popularity and availability of automobiles. The California State Legislature and governor enacted

268-496: A bridge that could handle differential settlement of the foundations. Engineers could more easily calculate the forces and stresses with a hinge in the girder. Heinrich Gerber was one of the engineers to obtain a patent for a hinged girder (1866) and is recognized as the first to build one. The Hassfurt Bridge over the Main river in Germany with a central span of 124 feet (38 metres)

335-455: A center anchorage. Rincon Hill is the western anchorage and touch-down for the San Francisco landing of the bridge connected by three shorter truss spans. The eastern crossing, between Yerba Buena Island and Oakland, was a cantilever bridge with a double-tower span, five medium truss spans, and a 14-section truss causeway . Due to earthquake concerns, the eastern crossing was replaced by

402-499: A dynamite blast on the eastern side of the island at 12:58 p.m. local time. Former President Herbert Hoover and Governor James Rolph were onsite; the two men were the first to turn over the earth with ceremonial golden spades. Other ceremonies took place simultaneously in San Francisco (on Rincon Hill ) and Oakland Harbor. The Yerba Buena Tunnel opened, along with the rest of the Bay Bridge, on November 12, 1936. As of 2019,

469-582: A former U.S. Congressman from California, traveled to Washington to help persuade President Herbert Hoover and the Reconstruction Finance Corporation to advance $ 62 million to build the bridge. Before work began, 12 massive underwater telephone cables were moved 1,000 feet (300 m) of the proposed bridge route by crews of the Pacific Telephone and Telegraph Co. during the summer of 1931. Construction began on July 9, 1933 after

536-418: A groundbreaking ceremony attended by former president Herbert Hoover , dignitaries, and local beauty queens. The western section of the bridge between San Francisco and Yerba Buena Island presented an enormous engineering challenge. The bay was up to 100 feet (30 m) deep in places and the soil required new foundation-laying techniques. A single main suspension span some 4,100 feet (1.2 km) in length

603-717: A law, effective in 1929, to establish the California Toll Bridge Authority (Stats. 1929, Chap 763) and to authorize it and the State Department of Public Works to build a bridge connecting San Francisco and Alameda County (Stats. 1929, Chap 762). The state appointed a commission to evaluate the idea and various designs for a bridge across the Bay, the Hoover-Young Commission . Its conclusions were made public in 1930. In January 1931, Charles H. Purcell ,

670-425: A new crossing that opened on Labor Day 2013. On Yerba Buena Island, the double-decked crossing is a 321-foot (98 m) concrete viaduct east of the west span's cable anchorage, the 540-foot (160 m) Yerba Buena Tunnel through the island's rocky central hill, another 790.8-foot (241.0 m) concrete viaduct, and a longer curved high-level steel truss viaduct that spans the final 1,169.7 feet (356.5 m) to

737-548: A project which created the artificial Treasure Island . The contract to build the Yerba Buena Cable Anchorage, Tunnel & Viaduct segment was opened for bids on March 28, 1933, and awarded to the low bidder, Clinton Construction Company of California, for $ 1,821,129.50 (equivalent to $ 34 million in 2023 ). Yerba Buena Island was the main site of the official groundbreaking for the Bay Bridge on July 9, 1933, when President Franklin D. Roosevelt remotely set off

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804-421: Is 76 feet (23 m) wide and 58 feet (18 m) high overall, and the dimensions of the tunnel interior are 66 feet (20 m) wide and 53 feet (16 m) high. In 1936, it was hailed as the world's largest-bore tunnel. The cross-sectional area of the upper half is 1,500 square feet (140 m ), and the lower half is 1,000 square feet (93 m ). Reminders of the long-gone bridge railway survive along

871-524: Is in use as an access to the EBMUD treatment plant) and onto 40th St. Due to falling ridership, Sacramento Northern and IER service ended in 1941. On September 13, 1942, a stop was opened at Yerba Buena Island to serve expanded wartime needs on adjacent Treasure Island. Despite the vital role the railroad played, the last train went over the bridge in April 1958. The tracks were removed and replaced with pavement on

938-778: The Bay Bridge , is a complex of bridges spanning San Francisco Bay in California . As part of Interstate 80 and the direct road between San Francisco and Oakland , it carries about 260,000 vehicles a day on its two decks. It includes one of the longest bridge spans in the United States . The toll bridge was conceived as early as the California gold rush days, with "Emperor" Joshua Norton famously advocating for it, but construction did not begin until 1933. Designed by Charles H. Purcell , and built by American Bridge Company , it opened on Thursday, November 12, 1936, six months before

1005-511: The Departments of War , Navy , and Commerce . The state applied for permits from the 3 federal departments as required. The permits were granted in January 1932, and formally presented in a ceremony on Yerba Buena Island on February 24, 1932. On May 25, 1931, Governor James Rolph Jr. signed into law two acts: one providing for the financing of state bridges by revenue bonds, and another creating

1072-552: The George Washington Bridge had a longer span between towers. As part of the celebration a United States commemorative coin was produced by the San Francisco Mint . A half dollar , the obverse portrays California's symbol, the grizzly bear , while the reverse presents a picture of the bridge spanning the bay. A total of 71,369 coins were sold, some from the bridge's tollbooths. The Yerba Buena passage utilizes

1139-514: The Golden Gate Bridge . It originally carried automobile traffic on its upper deck, with trucks, cars, buses and commuter trains on the lower, but after the Key System abandoned its rail service on April 20, 1958, the lower deck was converted to all-road traffic as well. On October 12, 1963, traffic was reconfigured to one way traffic on each deck, westbound on the upper deck, and eastbound on

1206-408: The Key System . Freight trains never used the bridge. The tracks left the lower deck in San Francisco just southwest of the end of 1st St. They then went along an elevated viaduct above city streets, looping around and into the terminal on its east end. Departing trains exited on the loop back onto the bridge. The loop continued to be used by buses until the terminal's closure in 2010. The tracks left

1273-458: The Navajo Bridge ) are built using pure cantilever spans from each side, with neither falsework below nor temporary supporting towers and cables above. These are then joined with a pin, usually after forcing the union point apart, and when jacks are removed and the bridge decking is added the bridge becomes a truss arch bridge . Such unsupported construction is only possible where appropriate rock

1340-544: The Yerba Buena Tunnel , also known as the Yerba Buena Island Tunnel . The tunnel is 76 feet (23 m) wide, 58 feet (18 m) high, and 540 feet (160 m) long. It is the largest diameter transportation bore tunnel in the world. The large amount of material that was excavated in boring the tunnel was used for a portion of the landfill over the shoals lying adjacent to Yerba Buena Island to its north,

1407-455: The median of the road for bridge employees; the parking lot is about 1,900 feet (580 m) long, stretching from about 800 feet (240 m) east of the toll plaza to about 100 feet (30 m) west of the metering lights. During the morning commute hours, traffic congestion on the westbound approach from Oakland stretches back through the MacArthur Maze interchange at the east end of

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1474-435: The 19th century understood that a bridge that was continuous across multiple supports would distribute the loads among them. This would result in lower stresses in the girder or truss and meant that longer spans could be built. Several 19th-century engineers patented continuous bridges with hinge points mid-span. The use of a hinge in the multi-span system presented the advantages of a statically determinate system and of

1541-703: The Authority purchased two private toll bridges, the San Mateo–Hayward Bridge and the Dumbarton Bridge . On November 7, 1952, the Authority authorized the issuance of the first bonds for the construction of the Richmond–San Rafael Bridge . On June 16, 1955, the Authority authorized the issuance of bonds for the construction of the Benicia–Martinez Bridge and a second Carquinez Bridge . On November 18, 1963, by state legislation,

1608-486: The Bay Bridge, including the construction of the Yerba Buena Tunnel. Before starting excavation, the ground through which the western half of the tunnel would be bored was stabilized by injecting cement grout under pressure through 25 1.5-inch (38 mm) holes bored into the loose rock over the crown of the tunnel. After excavating the western and eastern open portals, three drifts were bored from west to east along

1675-505: The Board of Supervisors, in which compromise with the Central Pacific was recommended; also the bridging of the bay at Ravenswood and the granting of railroad facilities at Mission Bay and on the water front. Wm. C. Ralston, ex-Mayor Selby and James Otis were on this committee. A daily newspaper attempts to account for the advice of these gentlemen to the city by hinting that they were afraid of

1742-594: The Division of San Francisco Bay Toll Crossings was re-named the "Division of Bay Toll Crossings", and established as a statutory unit of the State Department of Public Works. In 1959, the Authority authorized the issuance of bonds for the San Pedro-Terminal Island Bridge (subsequently re-named the Vincent Thomas Bridge ), but only after additional funding was obtained from the State of California as

1809-487: The San Francisco entrance to the bridge, was jammed with a slowly moving auto caravan. Every available policeman in the department was called to duty to aid in regulating the city's greatest parade of autos. One of the greatest traffic congestions of the evening was at Fifth and Mission Streets, with downtown traffic and bridge-bound traffic snarled in an almost hopeless mass. To add to the confusion, traffic signals jammed and did not synchronize. Police reported that there

1876-524: The San Francisco–Oakland Bay Bridge Division of the State Department of Public Works. On September 15, 1931, this new division opened its offices at 500 Sansome Street in San Francisco. During 1931, numerous aerial photographs were taken of the chosen route for the bridge and its approaches. That year, engineers had not determined the final design concept for the western span between San Francisco and Yerba Buena Island, although

1943-534: The State Highway Engineer of California, who had also served as the secretary of the Hoover-Young Commission, assumed the position of Chief Engineer for the Bay Bridge. Glenn B. Woodruff served as design engineer for the project. He explained in a 1936 article that several elements of the bridge required not only new designs, but also new theories of design. To make the bridge feasible, a route

2010-630: The Transbay Terminal ramps and Bay Bridge. The Key System handled buses over the bridge until 1960 when its successor, AC Transit , took over operations. It still handles service today, running to a new transbay terminal located in the same vicinity in San Francisco, the Salesforce Transit Center . Cantilever bridge A cantilever bridge is a bridge built using structures that project horizontally into space, supported on only one end (called cantilevers ). For small footbridges ,

2077-415: The action of the outer foundations. Cantilever Bridge.—A structure at least one portion of which acts as an anchorage for sustaining another portion which extends beyond the supporting pier. A simple cantilever span is formed by two cantilever arms extending from opposite sides of an obstacle to be crossed, meeting at the center. In a common variant, the suspended span , the cantilever arms do not meet in

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2144-411: The bay to Oakland was spanned by a 10,176-foot (3.102 km) combination of double cantilever, five long-span through-trusses, and a truss causeway, forming the longest bridge of its kind at the time. The cantilever section was longest in the nation and third-longest anywhere. Much of the original eastern section was founded upon treated wood pilings. Because of the very deep mud on the bay bottom, it

2211-496: The bonds were considered insufficient. On May 14, 1964, the Authority authorized the construction of the San Diego–Coronado Bridge . Overlapping authority over the operation of the various toll bridges existed with the Division of Highways Bridge Department, and with the Division of Bay Toll Crossings. San Francisco%E2%80%93Oakland Bay Bridge The San Francisco–Oakland Bay Bridge , commonly referred to as

2278-404: The bridge onto the three feeder highways, Interstate 580 , Interstate 880 , and I-80 toward Richmond . Since the number of lanes on the eastbound approach from San Francisco is structurally restricted, eastbound backups are also frequent during evening commute hours. The eastbound bottleneck is not the bridge itself, but the approach, which has just three lanes in each direction, in contrast to

2345-455: The bridge's five. The western section of the Bay Bridge is currently restricted to motorized freeway traffic. Pedestrians, bicycles, and other non-freeway vehicles are not allowed to cross this section. A project to add bicycle/pedestrian lanes to the western section has been proposed but is not finalized. A Caltrans bicycle shuttle operates between Oakland and San Francisco during peak commute hours for $ 1.00 each way. Freeway ramps next to

2412-423: The bridge, the new eastern section is a single deck carrying all eastbound and westbound lanes. Demolition of the old east span was completed on September 8, 2018. The bridge consists of two crossings, east and west of Yerba Buena Island , a natural mid-bay outcropping inside San Francisco city limits. The western crossing between Yerba Buena and downtown San Francisco has two complete suspension spans connected at

2479-594: The cantilever bridge. The toll plaza on the Oakland side (westbound traffic only since 1969) has eighteen toll lanes, with all charges now made either through the FasTrak electronic toll collection system or through invoices mailed through the USPS , based on the license plate of the car per Department of Motor Vehicle records. Metering signals are about 1,000 feet (300 m) west of the toll plaza. Two full-time bus-only lanes bypass

2546-491: The cantilevers may be simple beams ; however, large cantilever bridges designed to handle road or rail traffic use trusses built from structural steel , or box girders built from prestressed concrete . The steel truss cantilever bridge was a major engineering breakthrough when first put into practice, as it can span distances of over 1,500 feet (450 m), and can be more easily constructed at difficult crossings by virtue of using little or no falsework . Engineers in

2613-423: The center; instead, they support a central truss bridge which rests on the ends of the cantilever arms. The suspended span may be built off-site and lifted into place, or constructed in place using special travelling supports. A common way to construct steel truss and prestressed concrete cantilever spans is to counterbalance each cantilever arm with another cantilever arm projecting the opposite direction, forming

2680-676: The city would lose its position as the regional center of trade. Businessmen had considered the concept of a bridge spanning the San Francisco Bay since the Gold Rush days. During the 1870s, several newspaper articles explored the idea. In early 1872, a "Bay Bridge Committee" was hard at work on plans to construct a railroad bridge. The April 1872 issue of the San Francisco Real Estate Circular reported on this committee: The Bay Bridge Committee lately submitted its report to

2747-422: The construction of the Bay Bridge was part of the upper deck lining in late summer 1936. This included the emplacement of regularly spaced refuge bays ("deadman holes") along the south wall of the lower deck tunnel, escape alcoves common in all railway tunnels into which track maintenance workers could duck if a train came along. These remain and are visible to eastbound motorists today. The completed tunnel bore

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2814-507: The entrance to the bay, San Francisco was well placed to prosper during the California Gold Rush . Almost all goods not produced locally arrived by ship, as did numerous travelers and erstwhile miners. But after the first transcontinental railroad was completed in May 1869, San Francisco was on the wrong side of the Bay, and separated from the new rail link. Many San Franciscans feared that

2881-550: The former US president Herbert Hoover , Senator William G. McAdoo , and the Governor of California , Frank Merriam . Governor Merriam opened the bridge by cutting gold chains across it with an acetylene cutting torch . The San Francisco Chronicle report of November 13, 1936, read: the greatest traffic jam in the history of S.F., a dozen old-fashioned New Year's eves thrown into one – the biggest and most good-natured crowd of tens of thousands ever to try and walk

2948-648: The foundation piers. The Commodore Barry Bridge is an example of this type of cantilever bridge. Steel truss cantilevers support loads by tension of the upper members and compression of the lower ones. Commonly, the structure distributes the tension via the anchor arms to the outermost supports, while the compression is carried to the foundations beneath the central towers. Many truss cantilever bridges use pinned joints and are therefore statically determinate with no members carrying mixed loads. Prestressed concrete balanced cantilever bridges are often built using segmental construction . Some steel arch bridges (such as

3015-434: The idea of a double-span suspension bridge was already favored. In April 1932, the preliminary final plan and design of the bridge was presented by Chief Engineer Charles Purcell to Col. Walter E. Garrison, Director of the State Department of Public Works, and to Ralph Modjeski , head of the Board of Engineering Consultants. Both agencies approved and preparation of the final design proceeded. In 1932, Joseph R. Knowland ,

3082-430: The lower deck and the bridge was closed for a month. Reconstruction of the eastern section of the bridge as a causeway connected to a self-anchored suspension bridge began in 2002; the new eastern section opened September 2, 2013, at a reported cost of over $ 6.5 billion; the original estimate of $ 250 million was for a seismic retrofit of the existing span. Unlike the western section and the original eastern section of

3149-555: The lower deck in Oakland. The Interurban Electric Railway tracks ran along Engineer Road and over the Southern Pacific yard on trestles (some of it is still standing and visible from nearby roadways) onto the streets and dedicated right-of-ways in Berkeley, Albany, Oakland and Alameda. The Sacramento Northern and Key System tracks went under the SP tracks through a tunnel (which still exists and

3216-510: The lower deck, with trucks and buses also allowed on the upper deck. In 1986, the bridge was unofficially dedicated to former California governor James Rolph . The bridge has two sections of roughly equal length; the older western section, officially known as the Willie L. Brown Jr. Bridge (after former San Francisco Mayor and California State Assembly Speaker Willie L. Brown Jr. ), connects downtown San Francisco to Yerba Buena Island , and

3283-402: The newer east bay section connects the island to Oakland. The western section is a double suspension bridge with two decks, westbound traffic being carried on the upper deck while eastbound is carried on the lower one. The largest span of the original eastern section was a cantilever bridge . During the 1989 Loma Prieta earthquake , a portion of the eastern section's upper deck collapsed onto

3350-447: The path of the tunnel: one at the crown and the other two at the lower corners. The first drift broke through in July 1934, approximately one year after the start of construction. A ceremonial party led by Governor Merriam celebrated the completion of the first 12-foot-square (3.7 m) drift on July 24 by walking through it, followed by a short speech. The space between the three drifts

3417-499: The railroad company, and therefore made their recommendations to suit its interests. The self-proclaimed Emperor Norton decreed three times in 1872 that a suspension bridge be constructed to connect Oakland with San Francisco. In the third of these decrees, in September 1872, Norton, frustrated that nothing had happened, proclaimed: WHEREAS, we issued our decree ordering the citizens of San Francisco and Oakland to appropriate funds for

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3484-412: The south side of the lower Yerba Buena Tunnel. These are the regularly spaced refuge bays ("deadman holes"), escape alcoves common in all railway tunnels, along the wall, into which track maintenance workers could safely retreat if a train came along. (The north side, which always carried only motor traffic, lacks these holes.) The bridge opened on November 12, 1936, at 12:30 p.m. In attendance were

3551-426: The streets and guide their autos on them – This was the city last night, the night of the bridge opening with every auto owner in the bay region, seemingly, trying to crowd his machine onto the great bridge. And those who tried to view the brilliantly lighted structure from the hilltops and also view the fireworks display were numbered also in the thousands. Every intersection in the city, particularly those near

3618-431: The structural principles of the suspended span cantilever by sitting in chairs and supporting their colleague, Kaichi Watanabe , in between them, using just their arms and wooden poles. The suspended span, where Watanabe sits, is in the center. The wooden poles resist the compression of the lower chord , while the outstretched arms support the tension of the upper chord. The placement of the brick counterweights demonstrates

3685-629: The survey of a suspension bridge from Oakland Point via Goat Island; also for a tunnel; and to ascertain which is the best project; and whereas the said citizens have hitherto neglected to notice our said decree; and whereas we are determined our authority shall be fully respected; now, therefore, we do hereby command the arrest by the army of both the Boards of City Fathers if they persist in neglecting our decrees. Given under our royal hand and seal at San Francisco, this 17th day of September, 1872. Unlike most of Emperor Norton's eccentric ideas, his decree to build

3752-407: The toll booths and metering lights around the right (north) side of the toll plaza; other high occupancy vehicles can use these lanes during weekday morning and afternoon commute periods. The two far-left toll lanes are high-occupancy vehicle lanes during weekday commute periods. Radio and television traffic reports will often refer to congestion at the toll plaza, metering lights, or a parking lot in

3819-528: The tunnel lacks an official name. Construction of the Bridge Railway began on November 29, 1937, with the laying of the first ties. The first train was run across the Bay Bridge on September 23, 1938, a test run utilizing a Key System train consisting of two articulated units with California Governor Frank Merriam at the controls. On January 14, 1939, the San Francisco Transbay Terminal

3886-428: The tunnel provide access to Yerba Buena Island and Treasure Island . Because the toll plaza is on the Oakland side, the western span is a de facto non-tolled bridge; traffic between the island and the main part of San Francisco can freely cross back and forth. Those who only travel from Oakland to Yerba Buena Island, and not the entire length to the main part of San Francisco, still must pay the full toll. Developed at

3953-414: The tunnel roof and lower deck was excavated using a power shovel. By May 1935, work on removing the core was progressing and 40 steel ribs had been placed; concrete embedment was just starting. Removal of the core was completed on November 18, 1935. Once the excavation was complete, the upper deck was placed and the interior ceiling above the upper deck was lined with tiles. The last concrete poured during

4020-563: Was 275 feet (84 metres) deep and took full advantage of the fact that falsework, or temporary support, is not needed for the main span of a cantilever bridge. The Forth Bridge is a notable example of an early cantilever bridge. This bridge held the record for longest span in the world for twenty-nine years until it was surpassed by the Quebec Bridge . The engineers responsible for the bridge, Sir Benjamin Baker and Sir John Fowler , demonstrated

4087-440: Was chosen via Yerba Buena Island , which would reduce both the material and the labor needed. Since Yerba Buena Island was a U.S. Navy base at the time, the state had to gain approval from Congress for this purpose as it regulates and controls all federal lands and the armed services . After a great deal of lobbying, California received Congressional approval to use the island on February 20, 1931, subject to final approvals by

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4154-530: Was completed in 1867 and is recognized as the first modern cantilever bridge. The High Bridge of Kentucky by C. Shaler Smith (1877), the Niagara Cantilever Bridge by Charles Conrad Schneider (1883) and the Poughkeepsie Bridge by John Francis O'Rourke and Pomeroy P. Dickinson (1889) were all important early uses of the cantilever design. The Kentucky River Bridge spanned a gorge that

4221-418: Was considered but rejected, as it would have required too much fill and reduced wharfage space at San Francisco, had less vertical clearance for shipping, and cost more than the design ultimately adopted. The solution was to construct a massive concrete anchorage halfway between San Francisco and the island, and to build a main suspension span on each side of this central anchorage. East of Yerba Buena Island,

4288-585: Was dedicated. The following morning, January 15, 1939, the electric interurban trains started in revenue service, running along the south side of the lower deck of the bridge. The terminal originally was supposed to open at the same time as the Bay Bridge, but had been delayed. Trains over the Bridge Railway were operated by the Sacramento Northern Railroad ( Western Pacific ), the Interurban Electric Railway ( Southern Pacific ) and

4355-436: Was no lessening of the traffic over the bridge, all lanes being crowded with Oakland- or San-Francisco-bound machines far into the night. The total cost was US$ 77 million. Before opening the bridge was blessed by Cardinal Secretary of State Eugene Cardinal Pacelli , later Pope Pius XII . Because it was in effect two bridges strung together, the western spans were ranked the second and third largest suspension bridges . Only

4422-428: Was not practical to reach bedrock, although the lower levels of the mud are quite firm. Long wooden pilings were crafted from entire old-growth Douglas fir trees, which were driven through the soft mud to the firmer bottom layers. The construction project had casualties: twenty-four men would die while constructing the bridge. California Department of Transportation engineer C.H. Purcell served as chief engineer for

4489-429: Was then excavated, resulting in a single arch-shaped bore (in cross-section), and the tunnel roof was constructed using 16-inch (410 mm) steel I-beam ribs spaced 3 feet (0.91 m) apart to support the rock, which were then embedded in concrete up to 3 feet (0.91 m) thick at the crown. No cave-ins occurred during the excavation of the tunnel. After the roof was completed, the remaining core of rock between

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