The Engineering of the Golden Gate Bridge
A Monumental Beginning (Mid-1930s)
In the mid-1930s, two tall steel spires rose above the morning fog—towering 227 meters high and weighing 22,000 tons. These massive structures would soon become the towers of California’s Golden Gate Bridge. But at the time, they stood in Pennsylvania, where they had to be dismantled, packed, and shipped over 4,500 kilometers to the West Coast. Transporting the bridge towers across the country was just one of many challenges facing Charles Ellis and Joseph Strauss, the project’s lead engineers. Even before construction began, they encountered intense opposition.
Early Opposition and Doubts
The military feared the bridge would make a key harbor more vulnerable to attack. Ferry operators worried the new crossing would destroy their business. Local residents were determined to protect the area’s natural beauty. And many engineers believed the project was simply impossible. The Golden Gate Strait was notorious for its 96-kilometer-per-hour winds, powerful tides, frequent fog, and close proximity to the earthquake-prone San Andreas Fault.
Despite these concerns, Strauss was convinced the bridge could be built—and that it would finally give commuters a reliable way to reach San Francisco.
Choosing the Right Design
Although confident, Strauss initially proposed using a cantilever bridge. This design involves a large beam anchored at one end and extending outward like a diving board. Because such structures can only span a limited distance before collapsing under their own weight, Strauss planned to use two cantilevers connected at the center.
However, Charles Ellis and fellow engineer Leon Moisseif persuaded him to consider a suspension bridge instead.
Suspension Bridge Innovations
Unlike a cantilever structure supported from one end, a suspension bridge hangs its roadway from cables stretched across the span. This design is more flexible and better suited to withstand strong winds and shifting loads. The basic concept had existed for centuries in small rope bridges, but advances in steel manufacturing during the 1930s made it possible to create massive wire-bundle cables strong enough for large structures.
At the time, the Golden Gate Bridge would become the longest and tallest suspension bridge ever attempted—made possible only through these modern innovations.
Transporting and Reassembling the Towers
The enormous towers and cables could only be manufactured at major East Coast steel plants. Thanks to the recently completed Panama Canal, shipping them to California was feasible. Reassembling them on-site, however, brought new complications.
The north tower rested on relatively stable, shallow ground. In contrast, the south tower required building what was essentially a ten-story structure underwater.
Overcoming the Harsh Conditions of the Strait
The depth of the Golden Gate Strait made drilling or digging impossible. Engineers resorted to dropping explosives onto the ocean floor to create openings for the concrete foundations. A seawall was constructed to protect the site from fierce currents, and workers could only operate in 20-minute shifts between tides.
Inside the towers’ many compartments, workers carried detailed plans so they wouldn’t get lost. At one stage, an earthquake shook the south tower nearly five meters in each direction.
Safety Measures and Tragedy
Strauss placed strong emphasis on worker safety. He required hard hats and suspended a large safety net under the work area—an innovative idea at the time. Still, accidents occurred. In 1937, a scaffolding platform collapsed, plunging ten workers to their deaths despite the precautions.
Finishing the Structure
After the towers were completed, workers spun the massive cables on-site, installed vertical suspenders at regular 50-foot intervals, and poured the concrete roadway. With the structural work finished, one major task remained: painting the bridge.
Choosing the Iconic Color
The steel components arrived with a reddish primer coating, which protected the metal throughout construction. The U.S. Navy pushed for the bridge to be painted in black and yellow for visibility. However, consulting architect Irving Morrow believed the primer’s warm hue harmonized beautifully with the natural surroundings.
Backed by numerous letters from local residents, Morrow submitted a detailed 30-page argument advocating for an “international orange” finish. His recommendation prevailed, and the bridge was painted in the color that has since become its signature. Today, that vibrant orange stands out against the strait’s blue waters, green hills, and rolling fog.
*Image by wirestock on Freepik
