- So now, we're going to look at the second mentor
that I mentioned, Gustav Lindenthal, and who was he
because he also played an important role for Ammann.
So Lindenthal came from Austria to the US
and his mentoring, the teachings that he had with Ammann
was more of a practical experience
and the politics of bridge design,
two very important aspects.
So Ammann, actually in 1902, came to the US,
he found the US a great opportunity to become
a bridge designer, not unlike John Roebling,
when we talked about the Brooklyn Bridge.
So in 1902 Ammann came to the US,
and in 1912, Gustav Lindenthal hired Ammann.
And the project that Ammann worked on with Lindenthal
would be his first real major bridge design,
was for the Hell Gate Bridge on the East River.
And this is the East River, the same river
as the Brooklyn Bridge, but much further north.
So two proposals were put forward for this bridge,
one was a crescent arch shape,
and the other was called a spandrel braced arch.
So Lindenthal looked at both of these proposals
and considered both of them, but he liked very much
the towers, so those large towers are really what influenced
Lindenthal to choose the spandrel braced arch,
the design where the arch spreads and gets deeper
when it gets to that abutment.
Because this was Lindenthal's aesthetic, he really preferred
the massive to the light, he liked massive structures,
that was his aesthetic.
So the bridge was completed in 1916 and it was a bridge
for railroad loads, it wasn't for automobiles,
in 1916 we're still talking about the railroad
and this is what Lindenthal was designing, he was a famous
bridge designer for railroad bridges.
So the Hell Gate Bridge, aesthetically, you could look at it
and make a judgement for yourself, the elegance of it.
We're gonna look at it also from the efficiency
and economy point of view, so if you look at an image
of this bridge under construction, what you see is that
the top cord is not connected to that abutment structure
on the two ends, which means that all the load comes down
just to the bottom cord, that top cord there,
near the abutment, isn't doing any work.
So in a way, it's a little bit of a dishonest bridge
because when you look at it, it gives you that impression
that the bridge truss needs to get deeper
towards the abutment, but it actually doesn't.
That was an aesthetic choice that Lindenthal made.
So again, if you look at Lindenthal's aesthetic,
he tended to separate aesthetic from structure.
It wasn't a real honest expression
of what the structure was doing,
and he preferred the massive to the light as well.
But regardless, Lindenthal is an important engineer
that should be regarded as a great engineer,
in particular of railroad bridges.
We look at an image of it after it was completed,
the construction, and in this old photograph, you can see
Lindenthal and Ammann, so you see the relative size
of the scale of the two men.
David Billington would say that Lindenthal was
a very large man, and he was symbolic of the railroad age,
whereas Ammann was a very small-framed man,
and symbolic of the automobile age.
And we're gonna see that Ammann is gonna go on
to design, really, automobile bridges, not railroad bridges.
If we compare this old image after the completion
of the Hell Gate Bridge in 1916 to a more modern photograph
of the Hell Gate, you can see that the bridge remains
exactly the same, but the context, the culture surrounding
it has changed, very similar to that idea that I showed you
with the Brooklyn Bridge, contrasting the two images.
So on the right, you see the men in suits and top hats,
and on the left, you see an image of the bridge
as it looks like today, people are sunning in bikinis
and the men with no shirts, again it's a different culture,
the culture surrounding these bridges have changed
dramatically but the bridges remain exactly the same.
You can see this bridge, actually, if you're traveling
from train from New York to Boston.
You won't see it as you go under the bridge,
because if the train is under it,
you don't see it, it's right above you, but as the train
actually turns a corner, if you grab your camera quickly
you'll catch a sight of the Hell Gate Bridge
and I had that opportunity as I was traveling
to a conference with my colleague, Branko Glisic.
He and I were going to a conference in Boston,
I grabbed the camera, and there's Branko
with the Hell Gate Bridge in the background.