Building the impossible: Golden Gate Bridge - Alex Gendler
In the mid-1930s, two familiar spires
towered above the morning fog.
Stretching 227 meters into the sky,
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
over 4,500 kilometers away.
Moving the bridge’s towers
across a continent
was just one of the challenges
facing Charles Ellis and Joseph Strauss,
the project's lead engineers.
Even before construction began,
the pair faced all kinds of opposition.
The military feared the bridge
would make the important harbor
an even more vulnerable target.
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
more reliable passage to the city.
He was, however, a bit out of his depth.
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.
The result is a more flexible structure
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
for large-scale construction.
At the time, the Golden Gate Bridge
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
on the country’s east coast.
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
a ten-story building underwater.
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
to prevent getting lost.
And at one point, an earthquake rocked
the south tower
nearly 5 meters in each direction.
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,
carrying ten workers to their deaths.
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:
painting it.
After production, the steel had been
coated with a reddish paint primer
it maintained throughout construction.
But the Navy had been pushing hard
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.
Citing numerous letters from locals,
Morrow’s 30-page pitch
to paint the bridge “international orange”
beat out the Navy’s plans.
And today, this iconic color
still complements
the strait’s blue water, green hills,
and rolling fog.
