Happy Birthday, Golden Gate Bridge!

On May 27th, 1937, the new Golden Gate Bridge in San Francisco officially opened to pedestrian traffic. Vehicles weren’t allowed until the next day. Wired has a look at the bridge’s construction timeline stretching back to 1869, and some statistics.

The Golden Gate Bridge was an engineering marvel. The site alone — buffeted by high winds and split by the swirling currents of the Golden Gate — made construction treacherous. The sheer size of the bridge (the longest suspension bridge in the world until the Verrazano-Narrows Bridge opened in 1964) required several innovations in bridge-building technology, especially where it came to constructing the two colossal anchorages in — and under — turbulent water.

Of all the mind-boggling statistics surrounding the bridge’s construction, and there are plenty, perhaps the most jaw-dropping involves the two main suspension cables. Each measures 7,659 feet in length and each used hundreds of pencil-thick wires bound together to make a cable just over three feet in diameter. In all, more than 80,000 miles of steel wire was needed, enough to circle the earth three times.

Link

(image credit: jeromeinsf)