World's Tallest Bridge Towers

Long-span suspension bridges use tall towers to direct the pulling forces in the main cables upward so the cables can efficiently support the roadway deck. The bridge’s towers rose 746 feet tall (227 meters tall) and, when the bridge was completed in 1937, were the tallest bridge towers in the world. Workers built them by lifting prefabricated steel sections into place. A temporary climbing derrick was built between the two legs of each tower, and cranes on the platform lifted sections into place at that level. The platform and its cranes were then raised up the growing tower, and the process was repeated. Each tower contained 44,000 tons of steel (40,000 metric tons), manufactured at Bethlehem Steel plants in Pennsylvania and shipped through the Panama Canal to San Francisco Bay. Rising higher than a 60-story building, the towers demanded work at great heights, and workers sometimes took up to 20 minutes to climb ladders to their jobs.

San Francisco, California · United States