Construction

Construction
Construction began on January 5, 1933. The project cost more than $35 million ($514 million in 2018 dollars), and was completed ahead of schedule and $1.3 million under budget (equivalent to $24.2 million today). The Golden Gate Bridge construction project was carried out by the McClintic-Marshall Construction Co., a subsidiary of Bethlehem Steel Corporation founded by Howard H. McClintic and Charles D. Marshall, both of Lehigh University.

Until 1964, the Golden Gate Bridge had the longest suspension bridge main span in the world, at 4,200 feet (1,300 m). Since 1964 its main span length has been surpassed by fifteen bridges; it now has the second-longest main span in the Americas, after the Verrazzano-Narrows Bridge in New York City. The total length of the Golden Gate Bridge from abutment to abutment is 8,981 feet (2,737 m).

The Golden Gate Bridge's clearance above high water averages 220 feet (67 m) while its towers, at 746 feet (227 m) above the water, were the world's tallest on a suspension bridge until 1993 when it was surpassed by the Mezcala Bridge, in Mexico.

The weight of the roadway is hung from 250 pairs of vertical suspender ropes, which are attached to two main cables. The main cables pass over the two main towers and are fixed in concrete at each end. Each cable is made of 27,572 strands of wire. The total length of galvanized steel wire used to fabricate both main cables is estimated to be 80,000 miles (130,000 km). Each of the bridge's two towers has approximately 600,000 rivets.

In the 1960s, when the Bay Area Rapid Transit system (BART) was being planned, the engineering community had conflicting opinions about the feasibility of running train tracks north to Marin County over the bridge. In June 1961, consultants hired by BART completed a study that determined the bridge's suspension section was capable of supporting service on a new lower deck. In July 1961, one of the bridge's consulting engineers, Clifford Paine, disagreed with their conclusion. In January 1962, due to more conflicting reports on feasibility, the bridge's board of directors appointed an engineering review board to analyze all the reports. The review board's report, released in April 1962, concluded that running BART on the bridge was not advisable.

Excerpt from Wikipedia