- Hello and welcome back.
Today we are standing in front of
one of the world's most significant, most iconic bridges: the Brooklyn Bridge. So many of you know the Brooklyn Bridge.
If you've seen it in a photograph, you'll recognize it. But do you know the story behind the Brooklyn Bridge? Do you know the man who designed it, and his inspirations, and the will it took for him to do it? So today's lecture, we'll go over this history,
not only the scientific aspects of the Brooklyn Bridge,
where I'll talk to you about some terminology
that engineers use for design, but I also
will tell you the history of the Brooklyn Bridge,
and it's a dramatic story, and it's a great story.
I can only go through it in an abbreviated manner today.
I suggest that you read more about this
because it really is a tremendous story.
It was a tremendous feat of engineering to have
this bridge designed.
Last time, we talked about some bridges in the UK
and we left off with Stephenson and Brunel.
So Stephenson and Brunel were designing
some long-span bridges, and long-span,
for that period of time (this was the 1850s),
was on the order of 500 feet.
Today, we're going to look at John Roebling's
significant bridges and in particular three of them.
So we're going to look at the Niagara River Bridge
that he was designing around the same time
that Stephenson and Brunel were designing
their bridges in the US, except for the span
of the Niagara River Bridge is much longer
than what Stephenson and Brunel were doing.
Stephenson and Brunel and the Niagara River Bridge
were all bridges for railroads.
The other significant bridges by Roebling were
the Cincinnati Bridge and of course, the Brooklyn Bridge.
So we're going to start off by looking
at the Niagara River Bridge, touch upon
a little bit of the Cincinnati Bridge, which is a prototype
essentially to the Brooklyn Bridge.
But today's lecture is going to focus
on his masterpiece, the Brooklyn Bridge.
I like to start off my lectures
with introducing the engineer.
I think that the personality, the person,
plays an important role to having
these bridges designed and accomplished.
So these people not only have to have
a real strong technical understanding of the
mathematics, the engineering, but they also
in many cases have to have a strong will.
They had to persevere, and that is John Roebling's story.
So John Roebling came from Russia.
He graduated in 1826 from the Royal Polytechnic Institute
of Berlin, and before I continue telling you
about his experiences as an engineer,

I want to tell you a little bit about his personality.
What I tell my students is that
his personality matches his face.
So if you look at an image of John Roebling,
you see a very tough looking man, and
indeed, he was a tough man.
I read this book by David McCullough
called "The Great Bridge" and it's a great book
to understand not only the building of the Brooklyn Bridge,
but also the personality of John Roebling.
My impression from the research I did on John Roebling
is that he was certainly a man who was admired,
but admired from afar.
He wasn't a man that you would be
very friendly with, close up to.
He wasn't a very open person, opening up
and speaking of his feelings, so to speak.
He was emotionally and physically a very tough man.
He was a believer in hydropathy, the healing
powers of water, so for example, if he didn't
feel well at night, or whenever he didn't feel well,
he would sit in a scalding hot tub of water,
and then jump out and wrap himself
in ice cold sheets.
He would take cold baths every night, for example,
and he was known to drink concoctions of
raw egg, charcoal, turpentine and warm water.
So this was the kind of person he was,
an indicator of the kind of person
that he was, physically, very tough person.
He was a man of strong will.
If he was convinced he was right,
it was almost impossible to convince him otherwise.
So this is the backdrop to John Roebling,
a person of strong will, of physical
and emotional strength, and it took
that personality to make the Brooklyn Bridge a reality.
John Roebling was also a close friend and
a student of the philosopher Georg Hegel.
Georg Hegel, who author Alan Trachtenberg
wrote this about Hegel to describe him:
he said, quote, he inspired his students
with radical dreams of self-realization,
of personal cogency to realize one's potential.
This was the aspect of Hegel's system which
struck Roebling most forcefully.
Roebling, after graduating, he was an assistant
engineer and he had these high hopes
of being a designer of suspension bridges.
He was fascinated by the suspension bridges
that he was reading about, but he felt
that the German life wouldn't allow him
that opportunity.
He said that quote, the excessive bureaucracy,
end quote, of German society defeated his hopes.
He wrote in his diary that nothing
could be accomplished without quote, an army of
counselors, ministers, and other officials
discussing the matter for 10 years,
making long journeys and writing long reports,
while the money spent in all these preliminaries
comes to more than the actual
accomplishment of the enterprise."
So you can hear the dissatisfaction in his diary entry.
So inspired by Hegel's teaching, he sees America
as a new hope and in 1831, he leaves Europe for America.
He leaves with his brother and a small band
of German immigrants and they land
in Philadelphia on August 6, 1831.
They founded a German farm community near Pittsburgh
called Saxonburg, and he became
a farmer for six years.
But after six years, in 1837, he becomes bored
with farming and he takes a job with
the Pennsylvania state as an engineer.
One of his first responsibilities was
a survey for the Portage Railroad.
At that time, canals were a main source
of transportation, and when the canals
were blocked by mountains, the boats
were loaded onto railway trucks
and hauled over the mountains.
So there was an engine at the top of the
mountain, and the rope connecting the engine
to the truck was a six-inch thick hemp rope.
Now these ropes frayed easily, therefore they
were dangerous, and they had a short life span,
and therefore, they were expensive.
So Roebling saw an opportunity.
He developed a technique of spinning wires
to form wire rope, which was smaller,
stronger and lighter than hemp rope.
He was given this opportunity, and his wire rope
manufacturing business was born.
At first, this business was in Saxonburg, and then
in 1848, he moved it to Trenton, New Jersey.
The success of this business provided him
economic security and the freedom
to pursue his ambitions.
His career as a bridge builder began after
his wire rope business was established.
In 1845, he won a competition for a small aqueduct,
a seven span over the Allegheny River in Pittsburgh,
which was a suspension bridge.
Today, that suspension bridge is no longer in existence.
By 1850, Roebling had six suspension bridges
to his name, each one using rope
from his wire rope manufacturing company.
The oldest suspension bridge in the US
is one designed by Roebling in 1848,
the Delaware Acqueduct.
This bridge is still in existence today and
it is located near the intersection of
the three states of Pennsylvania,
New York and New Jersey.