SECTION 3
Read the text below and answer Questions 28-40.
San Francisco’s Golden Gale Bridge
A For several decades in the nineteenth century, there were calls to connect the rapidly growing metropolis of San Francisco to its neighbours across the mile-wide Golden Gate Strait, where San Francisco Bay opens onto the Pacific Ocean. Eventually, in 1919, officials asked the city engineer, Michael O’Shaughnessy, to explore the possibility of building a bridge. He began to consult engineers across the USA about the feasibility of doing so, and the cost. Most doubted whether a bridge could be built at all, or estimated that it would cost $100 million. However, a Chicago-based engineer named Joseph Strauss believed he could complete the project for a modest $25 to $30 million. After his proposal was accepted, Strauss set about convincing the communities on the northern end of the strait that the bridge would be to their benefit, as well as to that of San Francisco. With population centres growing fast, there was severe traffic congestion at the ferry docks, and motor vehicle travel by ferry was fast exceeding capacity.
B The bridge could not be constructed without the agreement of the US War Department, which owned the land on each side of the Strait and had the power to prevent any harbour construction that might affect shipping traffic. In 1924, San Francisco and Marin counties applied for a permit to build a bridge, and after hearing overwhelming arguments in favour of the project, the Secretary of War agreed. Despite the economic benefits promised by its supporters, the project met fierce resistance from a number of businesses – particularly ferry companies – and civic leaders. Not only would the bridge be an obstacle to shipping and spoil the bay’s natural beauty, they argued, it wouldn’t survive the sort of earthquake that had devastated the city in 1906. Eight years of legal actions followed as opponents tried to prevent it from being built.
C Meanwhile, Strauss’s team scrapped their original plans in favour of a suspension span capable of moving more than two feet to each side: this would withstand strong wind far better than a rigid structure. They also planned the two towers, and decided on a paint colour they called ‘international orange’.
D O’Shaughnessy, Strauss and the Secretary to the Mayor of San Francisco believed a special district needed to be created, with responsibility for planning, designing and financing construction. The formation of this district would enable all the counties affected by the bridge to have a say in the proceedings. This happened in 1928, when the California legislature passed an act to establish the Golden Gate Bridge and Highway District, consisting of six counties. In 1930, residents voted on the question of whether to put up their homes, their farms and their business properties as security for a $35 million bond issue to finance construction. The outcome was a large majority in favour. However, the District struggled to find a financial backer amid the difficulties of the Great Depression, a problem made worse by years of expensive legal proceedings. Now desperate, Strauss personally sought help from the President of Bank of America, who provided a crucial boost by agreeing to buy $6 million in bonds in 1932.
E Construction began in January 1933, with the excavation of a vast amount of rock to establish the bridge’s two anchorages – the structures in the ground that would take the tension from the suspension cables. The crew consisted of virtually anyone capable of withstanding the physical rigours of the job, as out-of-work cab drivers, farmers and clerks lined up for the chance to earn steady wages as ironworkers and cement mixers. The attempt to build what would be the first bridge support in the open ocean proved an immense challenge. Working from a long framework built out from the San Francisco side, divers plunged to depths of 90 feet through strong currents to blast away rock and remove the debris. The framework was damaged when it was struck by a ship in August 1933 and again during a powerful storm later in the year, setting construction back five months.
F The two towers were completed in June 1935, and a New Jersey-based company was appointed to handle the on-site construction of the suspension cables. Its engineers had mastered a technique in which individual steel wires were banded together in spools and carried across the length of the bridge on spinning wheels. Given a year to complete the task, they instead finished in just over six months, having spun more than 25,000 individual wires into each massive cable. The roadway was completed in April 1937, and the bridge officially opened to pedestrians the following month. The next day, President Roosevelt announced its opening via White House telegraph.
G The Golden Gate has endured as a marvel of modern engineering; its main span was the longest in the world for a suspension bridge until 1981, while its towers made it the tallest bridge of any type until 1993. It withstood a destructive earthquake in 1989 and was closed to traffic only three times in its first 75 years due to weather conditions. Believed to be the most, photographed bridge in the world, this landmark was named one of the seven civil engineering wonders of the United States by the American Society of Civil Engineers in 1994.