Golden Gate

Brief information

The Golden Gate Bridge was built where San Francisco’s short connection with Marin County had previously depended on ferries. Before it, crossing the bay took tens of minutes, and the city remained a rare major U.S. center that was served to a significant extent by ferries. That is why the bridge is important not only as a silhouette above the strait, but also as a permanent road across a place long considered almost unsuitable for such a structure.

The doubts were tied to the strait itself: wide water, strong tides, the depth in the middle of the channel, winds, and fog. After opening in 1937, the bridge became the largest suspension bridge in the world and kept that status until 1964. This fact helps one see it not as a familiar postcard image, but as an engineering response to a very inconvenient site.

What to notice right away

You can compare three levels of the bridge’s structure: the towers, the cables, and the roadway. The supports rise 227.4 meters above the water, while the roadway hangs on suspender ropes attached to two main cables. Each cable is encased in a steel covering, has a diameter of 924 mm, and is made up of more than 27 thousand steel wires. Thus the scale here is read not only from the span’s length, but from how many separate metal threads work as one system.

It is also worth noticing the maintenance details. Between the lanes there is a movable solid barrier: it was introduced after accidents involving vehicles crossing into oncoming traffic, and it allows the number of lanes in each direction to be changed. The paint is not just a color either: from the 1960s onward, old lead layers were replaced with corrosion protection and then an outer acrylic coating. Another noticeable detail is the special phones along the span for contacting a crisis center. They sharply change how the bridge is read: alongside the engineering triumph, one can see the constant work of dealing with risk.