- So I mentioned that the Bayonne Bridge was the longest
spanning arch bridge in the world when completed,
but so was the George Washington Bridge, right behind me.
How is it that we got to this span of 3,500 feet, which was
an enormous span, remember that the Brooklyn Bridge,
that we just spoke about, was 1,600 feet in span,
and that was tremendous, that was just unbelievable
for the people at the time to see a bridge of that span.
Now at the time that proposals were being put forward
for crossing this Hudson River, the longest spanning bridge
in the world was the Benjamin Franklin Bridge,
and that span was 1,750 feet.
So we needed to go from the longest spanning 1,750 feet,
to on the order of 3,500 feet.
I have a great colleague, Steve Buonopane,
at Bucknell University, and he put together this plot
that I'm showing on the screen right now,
which shows the different span records for the years.
So we see that every year, the record span increases just
a little bit and a little bit more and a little bit more.
So we have the Brooklyn Bridge reached record,
and then the Benjamin Franklin Bridge
reached the world's record,
but to get to cross this river, we see the tremendous jump
that we need to make, so it was a huge leap in engineering
to jump from on the order of 1,700 feet to 3,500 feet.
Ammann had to essentially double the record
for the world's longest span.
So how did he do that, and what was he thinking?
Well here's an image of his vision
for the Hudson River crossing, it was a vision
of a suspension bridge with stone towers.
But how did he get there?
He was working for Lindenthal at the time,
and Lindenthal had put forward proposals, remember he had
a proposal in the book by Wilhelm Ritter in 1888
for crossing this, and in 1920, he'll put together
another proposal, but all of these proposals were
for railroad bridges, Lindenthal was in the railroad age
and he wanted a railroad bridge.
And this bridge that Lindenthal was proposing to put forward
was going to be very large and very expensive.
So as I mentioned, in 1888 Lindenthal put together
a proposal and then there were several other people
who put proposals, there was another one in 1889 by others,
others, 1893, another proposal by others in 1894,
1896, another one, 1913, so you'll see these images
of the different ideas and different proposals
but they were all very long spanning bridges
crossing the Hudson River.
In 1920, Lindenthal put forward another proposal
and he and Ammann worked on this proposal
for several years.
Lindenthal needed to raise money for this proposal
for this bridge to be built, so he put together a company
called the North River Bridge Company
and started raising money privately for the design
of his proposal for this bridge.
So Ammann is working with Lindenthal
from 1920 until 1923
on Lindenthal's plans for this gigantic proposal
of the Hudson River crossing.
But Ammann grows concerned, he's concerned because, first,
of the huge cost of this bridge, Ammann knows that the cost
of Lindenthal's proposal is tremendous and is not optimistic
that Lindenthal will be able to raise the funds
for this massive bridge.
Also there is a reluctance from the railroads to committ
to using the bridge, and then finally, there's opposition
of the Manhattan businesses, because there would be
twenty lanes of traffic entering mid-town,
which was the proposed site of Lindenthal's bridge,
Lindenthal proposed that the bridge be built at mid-town.
So many businesses were concerned they would need that
land space now for that railroad to pass by.
So for these reasons, Ammann was concerned.
What did he envision, what did Ammann want?
He wanted an automobile bridge, he was trying to convince
Lindenthal that the time was now to build an automobile
bridge not a railroad bridge, and to build it
in northern Manhattan where land was less expensive,
not in mid-town Manhattan.
So he tried to convince Lindenthal of these ideas
but Lindenthal was still supportive of his own ideas,
his proposal for a railroad bridge in mid-town.
So Ammann can't convince Lindenthal of his ideas,
and in 1923 he leaves Lindenthal's company
and begins a period of unemployment
and during this period of unemployment, Ammann continues
to work on his ideas for the design of what we now know
to be the George Washington Bridge.
So next, let's look at the scientific, social, and symbolic
aspects of the George Washington Bridge
and see how Ammann was able to not only design this
from an engineering perspective, but also, from the social
part of the story, convince the politicians
and the community about this bridge
and this idea that he had.