Name: Building the impossible: Golden Gate Bridge - Alex Gendler
Uploaded: 2022-02-26T03:23:13.000Z
Duration: 5 min 27 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

In the mid-1930s, two familiar spires towered above the morning fog.

these 22,000-ton towers would help support California's Golden Gate Bridge.

But since they were currently in Pennsylvania,

they first had to be dismantled, packaged, and shipped piece by piece

Moving the bridge's towers  across a continent

was just one of the challenges  facing Charles Ellis and Joseph Strauss,

Even before construction began,  the pair faced all kinds of opposition.

The military feared the bridge  would make the important harbor

Ferry companies claimed the bridge would steal their business,

and residents wanted to preserve the area's natural scenery.

Worse still, many engineers thought the project was impossible.

The Golden Gate Strait was home  to 96-kilometer-per-hour winds,

swirling tides, an endless blanket of fog,

and the earthquake-prone  San Andreas fault.

But Strauss was convinced  the bridge could be built;

and that it would provide  San Francisco's commuters

Strauss's initial plans to span the strait used a cantilever bridge.

This kind of bridge consists  of a single beam anchored at one end

and extended horizontally like a diving board.

Since these bridges can only extend so far before collapsing under their own weight,

Strauss's design used two cantilevers, linked by a structure in the middle.

But Ellis and his colleague Leon Moisseif convinced Strauss

to pursue a different approach: the suspension bridge.

Where a cantilever bridge is supported from one end

a suspension bridge suspends its deck from cables strung across the gap.

that's resilient to winds  and shifting loads.

This kind of design had long been used  for small rope bridges.

And in the 1930s,  advanced steel manufacturing

could create cables of bundled wire  to act as strong steel rope

was the longest and tallest  suspension bridge ever attempted,

and its design was only possible due to these innovations.

But cables and towers of this size  could only be built at large steelworks

While the recently completed Panama Canal

made it possible to ship these components to California,

reassembling the towers on site  didn't go quite as smoothly.

It was relatively easy to find a stable, shallow foundation for the north tower.

But building the south tower  essentially required erecting

Since the strait's depth prevented them drilling or digging the foundations,

bombs were dropped on the ocean floor, creating openings for pouring concrete.

A seawall was built to protect the site from powerful currents,

and workers operated in 20-minute shifts between tides.

The towers had so many compartments that each worker carried a set of plans

And at one point, an earthquake rocked the south tower

Strauss took worker safety very seriously, requiring hard hats at all times

and stretching a safety net  below the towers.

But not even these precautions  could prevent

an entire scaffolding platform from falling in 1937,

Once the towers were complete,  workers spun the cables in place,

hung suspenders at 50-foot intervals, and laid down the concrete roadway.

The bridge was finished, but there was still one more task ahead:

After production, the steel had been  coated with a reddish paint primer

to paint the bridge  a tactical black and yellow.

Consulting architect Irving Morrow  actually thought the primer itself

paired nicely with the strait's  natural backdrop— and he wasn't alone.

Morrow's 30-page pitch  to paint the bridge “international orange”

And today, this iconic color  still complements

the strait's blue water, green hills,  and rolling fog.