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The Famous Golden Gate Bridge
Sure, you know what the Golden Gate Bridge looks like. But do you know why it flexes 16 feet side-to-side, or that its cables could circle the equator three times?
From the weird color name (blame gold rush geography) to its neverending paint job, this bridge has stories that go way deeper than its famous fog photos.
How the Bridge Gets Its Endless Paint Job
A team of 38 skilled painters works on the Golden Gate Bridge throughout the year, no matter the weather. They must start painting the bridge again as soon as they finish, as there’s always another spot that needs attention. Salt from the Pacific Ocean, thick fog, and strong winds keep wearing away at the paint.
The team uses between 5,000 and 10,000 gallons of special zinc-rich paint each year to protect the bridge’s 83,000 tons of steel. To reach every part of the bridge, painters sit in special chairs and use movable platforms, often working hundreds of feet above the water.
World War II Bunkers Remain Under the Bridge
The southern end of the bridge sits above hidden military bunkers built during World War II. These concrete rooms, called Battery Lancaster, were made to protect the bridge and bay from Japanese warships. At their busiest, the bunkers held 150 soldiers and lots of weapons, including 6-inch guns and anti-aircraft guns.
The military also put special nets across the bay to stop enemy submarines from entering. The bunkers were built to last, with walls 12 feet thick that could survive direct hits while giving soldiers a clear view across the bay entrance.
Why the Bridge Can Bend Without Breaking
The bridge’s towers can move sideways up to 16 feet without getting damaged. Engineers designed this flexibility on purpose to help the bridge handle strong Pacific storms with winds over 70 miles per hour.
Special joints let the road and towers move when they need to. On hot summer days, the middle of the bridge can rise up to 16 feet, and the towers can lean up to 12 inches to either side. This clever design proved its worth during the big 1989 Loma Prieta earthquake, when the bridge swayed but stayed strong.
Main Cables Hold More Than Meets the Eye
Looking up at the Golden Gate Bridge’s main cables, you’d never guess what’s inside them. Each thick cable, measuring 36.5 inches around, contains 27,572 thin steel wires bundled together in a hexagon shape.
Workers made these cables by passing wheels of wire back and forth across the gap 808 times. If you took apart just one main cable and laid out all its wire, it would stretch 80,000 miles – enough to go around Earth three times. These powerful cables hold up the 887,000-ton bridge while handling pulls of up to 61,000 tons each.
Ocean Life Thrives Around Bridge Supports
The concrete bases of the bridge have created new homes for sea creatures, reaching 100 feet down into the bay. These underwater structures now support large groups of colorful sea anemones and red rock crabs. Fast-moving water flows through the Golden Gate at speeds up to 7.5 knots, bringing food for all these animals.
Different kinds of rockfish, including copper and brown ones, have made permanent homes around the concrete pillars. Scientists have found more than 100 different types of sea life living in this human-made habitat.
Safety Features That Changed Construction Work
When building the Golden Gate Bridge in the 1930s, the workers used new safety gear that changed construction sites forever. After a falling rivet hit someone, wearing hard hats became a rule, leading to the first successful hard hat design by E.D. Bullard Company.
Workers also had a giant safety net hanging 60 feet below them. This net saved 19 people who fell, and they became known as the ‘Halfway to Hell Club.’ Sadly, ten workers died near the end when their scaffold broke through the net.
Effects of San Francisco’s Famous Fog
The fog that rolls through the Golden Gate got its nickname ‘Karl’ from locals in 2010. It forms when warm air from inland meets cool air from the Pacific Ocean, creating an impressive sight.
This thick fog shows up about 300 days each year, sometimes making it hard to see more than a few feet ahead. To help boats stay safe, the bridge has fog horns that make different sounds – two short blasts every 30 seconds from the south tower and one long blast from the north tower.
Earthquake Protection Built Into the Bridge
Special devices similar to car shock absorbers, but much bigger, help protect the Golden Gate Bridge during earthquakes. The bridge can flex and move without getting damaged, thanks to its smart design and special base supports.
Seventy-six sensors constantly check how the bridge moves and whether it’s staying healthy. Engineers have been adding earthquake protection since 1997, making the bridge strong enough to handle earthquakes up to 8.3 on the Richter scale.
How Rivets Hold the Bridge Together
The Golden Gate Bridge stays strong thanks to 600,000 rivets, each heated to exactly 1,800 degrees before being put in place. As these rivets cooled down, they shrank and created very tight connections.
Four-person teams installed each rivet – one person heated it, another threw it, a third caught it, and the fourth secured it. When workers need to replace old rivets today, they use special tools that copy the original 60,000 pounds of pressure used to install them.
Special Paint Protects Against Ocean Air
The bridge’s orange paint isn’t ordinary – it’s a special mix made just for the tough ocean environment. It has three layers: a zinc base layer, a middle protective layer, and a top orange layer that fights rust and sun damage.
Each layer does a specific job to protect the steel, and together they make a coating as thick as six sheets of paper. The exact recipe for this paint is kept secret and protected by patents, though it keeps getting better based on how well it works.
Unique Sounds the Bridge Makes
Strong winds create different sounds as they pass through the bridge’s railings. When winds go faster than 35 miles per hour, they make musical tones you can hear up to three miles away.
In 2020, workers changed the western railing by adding angled slats to reduce the humming sound that bothered nearby residents. The bridge’s fog horns add their own music – the south tower plays a low B flat note, while the north tower makes a higher F sharp sound.
Last Piece of Construction Creates a Puzzle
When workers tried to connect the final pieces of the Golden Gate Bridge, they hit an unexpected problem. The two sides didn’t line up because of a 12-degree temperature difference between them, leaving a 42-inch gap.
The team could only join the sides when both parts were the same temperature. At 3:30 AM on November 18, 1936, they finally found the right moment and connected the spans using special expanding joints.
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