by Roma Agrawal
By a majority of just three votes, the men agreed to let Washington Roebling continue running the project until its completion. Nearly half a lifetime later, when Roebling was asked what part Emily had played in building the bridge, he answered ‘her remarkable talent as a peacemaker’ among the divisive personalities involved in the bridge’s construction. I like to think of her as the polished negotiator: patiently listening to every side of the numerous arguments, offering tactful words of caution to the men, and smoothing difficulties in a highly-charged political atmosphere. Emily was clearly instrumental in ensuring her family’s legacy remained intact.
Before the bridge was opened to the public, one final test had to be conducted: checking the effect of a trotting horse on the structure. Even at that time, the dangers of resonance – movement caused by users of a bridge – were well understood, so precautions were taken to establish that the bridge was stable and safe for different modes of transport. Carrying a live rooster as a symbol of victory, Emily was the first person to ride across the bridge in a horse-drawn carriage.
A few weeks later, on 24 May 1883, she was given the honour of accompanying President Chester Arthur’s procession as he officially opened the bridge, while her husband watched on proudly through a telescope from his room. The day – which came to be known as ‘The People’s Day’ – was declared an official holiday in Brooklyn. Fifty thousand residents spilled into the streets, celebrating and hoping to catch a glimpse of their President and their new bridge. Numerous speeches revered the bridge as a ‘wonder of science’, and an ‘astounding exhibition of the power of man to change the face of nature’. Or, in this case, the power of woman. During the ceremonies, Abram Hewitt, one of Washington Roebling’s competitors, stated: ‘The name of Emily Warren Roebling will . . . be inseparably associated with all that is admirable in human nature and all that is wonderful in the constructive world of art,’ and called the bridge ‘. . . an everlasting monument to the self-sacrificing devotion of a woman and of her capacity for that higher education from which she has been too long disbarred’.
The official opening ceremony of the Brooklyn Bridge.
Today, on one of the towers supporting the bridge there is a bronze plaque dedicated to the memory of Emily, her husband and her father-in-law. Placed there by the Brooklyn Engineers’ Club, it reads:
‘The Builders of the Bridge
Dedicated to the memory of
EMILY WARREN ROEBLING
1843 – 1903
Whose faith and courage helped her stricken husband
COL. WASHINGTON A. ROEBLING. C.E.
1837 – 1926
Complete the construction of this bridge
From the plans of his father
JOHN A. ROEBLING. C.E.
1806 – 1869
Who gave his life to the bridge
“Back of every great work we can find
The self-sacrificing devotion of a woman”’
Emily Warren Roebling was technically brilliant and liked by just about everyone she ever worked with. She was held in high esteem and shown great respect by the forces behind the bridge, regardless of their role or aspiration for the project. That she, as a woman, could traverse every social circle, and was welcomed by politicians, engineers and workers, her opinions heeded and instructions followed, was in itself proof of her exceptional skills, in an age when a woman’s presence on a construction site was unheard of.
The commemorative plaque to the Roebling family on the Brooklyn Bridge.
As a young structural engineer at a similar age to Emily when she was working on the bridge, I am well aware of the challenges and pressures involved in constructing a key architectural landmark in a major world city. But I came to my greatest engineering challenges after years of structured technical training, experience, guidance and support – gaining my chartered engineer’s qualification on the way. Emily did it without any formal training; she was not even a qualified engineer. Tragic circumstances forced her into a situation in which she never expected to find herself, yet she excelled and triumphed. This was not just any bridge – its 486m span made it by far the longest bridge of its time. It was the first to use steel wires for suspension cables, and the first to employ caissons of such enormous size, and explosives within them. It was a pioneering structure that has persisted to this day.
In my research I have been surprised to see the disparity in the way Emily’s contribution is acknowledged by commentators. In some places, she is highlighted as the true force behind the project. In other sources, there is absolutely no mention of her at all. But, compared to equivalent women of her time, her contribution has received some recognition at least. I am delighted that her name endures on the commemorative plaque. She is an inspiration to me because, despite the monumental challenges she faced, she delivered the most advanced bridge of its time, using every skill an engineer needs – technical knowledge, the ability to communicate with labourers and persuade stakeholders, and tenacity – at a time when women were expected to be silent and inconsequential.
BRIDGE
‘Flirtman called again. Managed to get rid of him in only 3 minutes and 23 seconds.’
At a party, I had been introduced to a man who chattered away at me, altogether too suave and flirtatious for my liking – or rather, the type that considers himself suave but isn’t really. Eventually I extricated myself and was careful to steer clear of him for the rest of the evening. But not quite careful enough – somehow we ended up swapping phone numbers.
Over the next few weeks, he called me a couple of times. The first time, my mum had just arrived from India, so I fobbed him off with a polite, ‘Sorry, my mother has just arrived, I can’t talk now.’ The second time I got rid of him in just over three minutes, and proudly emailed a friend to tell her so.
But Flirtman – as he’d become known to me and my friend – was persistent. He called and emailed a few more times (the conversations began to extend past three minutes). Finally, I agreed to go on a date with him. It was then that I found out something unexpected about this young man – he was a complete geek. We talked about physics, programming, architecture, history; and I discovered that he spent hours reading Wikipedia, and that his brain had an uncanny capacity for interesting but essentially useless facts. I left dinner hiding the little flutter I felt.
I can’t think how it happened, but over the course of that dinner Flirtman spotted that I too am a bit of a nerd, and he developed a cunning strategy to get my attention. The morning after our first date, I opened my emails to see a message headed: ‘Bridge of the Day no. 1’.
‘An example of why you should do a proper damping analysis,’ read the email: it was the Tacoma Narrows Bridge in Washington which collapsed dramatically in 1940 in a relatively light wind. Each morning after that I’d log on, still half asleep, and a grin would spread across my normally grumpy face as I saw that a new Bridge of the Day had appeared. In fact, for a whole week, he found and sent me a Wikipedia link and a picture of a bridge: one which had a funny story, a unique design, had suffered a catastrophic failure or just looked beautiful. Was I that obvious? Surely it couldn’t be that simple to win me over . . .
Even though I still thought of the sender of the emails as slightly trying, I enjoyed his bridge stories, and learned about examples I hadn’t even heard of. After a week of such offerings, I at least had to acknowledge that he’d pulled off a pretty good chat-up line. It’s not every day you get serenaded by a series of bridges. And so, in honour of Flirtman, here is my version of Bridge of the Day. I’ve chosen five of my favourite examples from around the world – but unusual or obscure ones that, hopefully, you haven’t heard of. Each bridge is made from different materials, ranging from silk to steel. I’ve chosen them from different periods in history, and they demonstrate different methods engineers had for building. One bridge moves because it’s designed to, one is unintentionally bouncy, and one was made by an ancient king. Each has its own unique engineering feat
ure – offering a glimpse into the thousands of creative ways that humans have crossed valleys and rivers through the ages.
No. 1: Old London Bridge
Old London Bridge: that was often falling down.
This isn’t a bridge I’ve seen, because it was finally demolished in 1831. With its tumultuous history it holds an air of mystery for me: it’s the legendary bridge – built thanks to the passion and perseverance of one person – that spanned the Thames for more than 600 years. What fascinates me above all is that for centuries it served the people of London faithfully – but, ultimately, badly. Despite its impressive longevity, Old London Bridge failed as a structure.
The Romans, as you might expect, were industrious and efficient bridge-builders. But after their western empire declined in the fourth and fifth centuries ad, very few bridges were built until the 1100s. At that point, the Church started to fund and construct a large number of bridges. Many of these had chapels where one could pray for safe passage, and contribute financially to its upkeep. There is a legend that Saint Bénézet (who was inspired by a vision to build the famous Pont d’Avignon) founded the Fratres Pontifices or ‘Brothers of the Bridge’, who built bridges wherever they were needed for religious or community purposes.
Spurred on by this development, Peter of Colechurch, curate of a small chapel in London, decided to raise funds to build a new bridge over the River Thames in 1176. He collected donations from the king, peasants, and everyone in between, in order to build the first stone bridge in London. Previously there had been a wooden bridge that had been variously destroyed by storm, fire, military strategy or simple neglect. Building this structure, however, would prove to be a big challenge for Peter, as it was the first time anyone had proposed a bridge with stone foundations in a tidal river. The Thames is not an easy stretch of water to bridge: it moves up and down by almost 5m, has a very muddy bed, and contains fast-flowing water, making it extremely difficult to build the foundations and piers to support the deck. Even getting materials to the site promised to be a struggle, as stone had to be bumpily transported over the poor-quality cobbled roads provided for travellers. Undaunted, Peter took on this mammoth task.
People in medieval London must have been dumbfounded by the elaborate construction of their first stone bridge. They would have heard the ear-splitting thuds of the piledrivers, mounted on barges, which slowly wound up a large weight, then dropped it to whack piles into the riverbed. They would then have seen artificial islands called starlings built on top of the piles. Each was shaped like a rowing boat, and was constructed by amassing stones and rocks of different sizes. The starlings – and the piers or columns that rose from them to support the deck of the bridge – were huge and irregular in size, ranging from 5m to 8m in width. The populace watched as carpenters attached wooden skeletons shaped like arches to the piers. These were centering, on top of which carved stone was placed (after it had been perilously lifted from barges) to create the arches. The people of London had to wait an entire year to see just one arch completed.
In 1209, 33 years later, the bridge – which was 280m long and nearly 8m wide – was completed, but Peter of Colechurch did not live to see it. He died after 29 years of service to the structure, and was buried in the crypt of its chapel.
The finished bridge was extremely crude. It had 19 arches of different shapes and sizes, made from randomly cut stone in the pointed Gothic style. Although the pointed arch inspired by Islamic architecture was all the rage in buildings and churches at the time, it was not an efficient shape to use for a bridge. Certainly, such arches allowed medieval churches to be taller than ever before – but the bridge didn’t need to be tall, it needed to be the right height to link both sides of the river. A more traditional semicircular Roman arch would have been more appropriate, but it looks like the engineers were going for style over substance. At its centre was a drawbridge to allow tall ships to pass through, and each end was surmounted by a defensive gatehouse.
The River Thames rises and falls with the tides. By blocking nearly two-thirds of it, the overly broad starlings and piers of the bridge severely restricted the natural flow of the river. So, when the tide turned, the water was much higher on one side of the bridge than the other, because it couldn’t flow past, and the choked water created deadly rapids. All but the most foolish sailors avoided passing under the bridge during those times, for fear that their boats would overturn, casting them into the river. But hundreds died. Maybe their lives would have been saved had they paid heed to the saying, inspired by the bridge, which cautioned that it was made ‘for wise men to pass over, and for fools to pass under’.
To make matters worse, houses began appearing on the bridge. Now, I like the idea of living on a bridge – watching the river change as the day went on and enjoying spectacular sunsets would undoubtedly have been an uplifting experience. This has worked beautifully on the Ponte Vecchio in Florence in Italy, where the carefully planned and executed houses and shops create a feeling of peace and civic order. By contrast, the houses on London Bridge only added to the chaos.
Squashed between the carriageway and the edge of the structure, numerous three- and four-storey houses and shops were built, until there were over a hundred such dwellings. Temporary stalls were set up in front where shopkeepers sold their wares. Public latrines overhung the sides of the structure, discharging waste directly into the river below. The bridge had not been designed for the weight of the buildings, and the buildings themselves were not safely separated from one another, creating a huge fire risk. The bridge really was an accident waiting to happen. Most of the houses were destroyed by a fire in 1212, along with thousands of unfortunate people who had crowded onto the bridge to watch the flames take hold at one end – but then strong winds carried embers to the opposite end and started a new fire, trapping them in the middle. More than 3,000 bodies were found severely or partially burned, and many more were reduced to unidentifiable ashes. In 1381 and 1450, revolts and rebellions again laid waste to many parts of the bridge.
By the fifteenth century, the buildings on the bridge had doubled both in number and in height. These tall, overhanging structures created dark and dismal passages through which carts, wagons, cattle and pedestrians fought their way. At peak times it could take an hour to cross. Between the overloading of the bridge by the houses, the effects of fires, and the wearing away of the supporting piers by the rapids flowing between them, some portion of the structure was always crumbling and collapsing into the water.
In 1633 a third of the homes were destroyed by yet another fire, although this was perhaps a blessing in disguise, because it created a gap between houses on the bank and those on the bridge. This probably saved the structure from disaster in 1666, when the Great Fire of London couldn’t spread across this void. It was, quite literally, a narrow escape, but it seems that the residents and shopkeepers didn’t learn their lesson. Another fire in 1725 destroyed over 60 houses and two of the arches.
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The houses were finally demolished in 1757, and the bridge survived past the turn of the century until 1832, when the new London Bridge (designed by civil engineer John Rennie) was constructed alongside it. But the original bridge is still firmly embedded in our culture – when I was little, my mother taught me the nursery rhyme inspired by its precarious history, singing, ‘London Bridge is falling down, my fair lady’ in her slightly accented, out-of-tune voice. It’s a rare song about engineering. It teaches the future engineers among us about the perils of bad design before we can even walk.
No. 2: The Pontoon
The Pontoon: bridging the sea with boats.
When we think of a bridge, we usually picture something high up in the air, neatly straddling the obstruction it needs to avoid. My second bridge, however, defies this image. Seeking revenge, the ancient Persian king Xerxes built an immense ‘bridge’ to cross nothing less than the sea. But instead of flying over the water, he used its buoyancy to create a unique bridge, known as a po
ntoon.
Xerxes’ father, Darius I, was one of the greatest emperors in history, ruling unopposed from the steppes of central Asia to the tip of Anatolia. His empire was far larger than Alexander the Great’s (and, under his successors, it grew larger still). Between 492 and 490 BC he decided that the tiny Greek city states must fall under his rule, and he marched to Marathon to battle an army from Athens and Plataea. His surprise defeat there marked the end of the first Persian invasion of Greece.
Darius had planned a second attempt but died before he could fulfil his plans. Xerxes never forgot the humiliation his father had faced at Marathon, and was determined to fulfil Darius’ dream of bringing the Greek states under the heel of the Persian Empire. Xerxes spent years training soldiers, planning and accumulating supplies before he attacked, and once again, while most of the Greek states submitted to him, he faced resistence from the Athenians and the fierce warriors of Sparta.
A challenge arose in 480 BC when the Persian army needed to march into Thrace via the Hellespont, the strait (now known as the Dardanelles) that separates modern-day European and Asian Turkey. After the first attempt at a crossing failed when a violent storm destroyed the bridges the Phoenicians and Egyptians had built, Xerxes ordered that the waters be given 300 lashes for their insolence. And he had the engineers who built the two failed bridges beheaded.
The replacement engineers, presumably in a bid to save their necks, built a much more substantial structure. The Persians had to travel 1.5km across a deep strait – at the time a huge distance to span, and very difficult to do using the traditional bridging technique, which was to build foundations underwater on solid ground and then span material between supports. Instead, as Herodotus tells us in The Histories, they gathered 674 ships (a combination of penteconters, Greek ships with 50 oars, and triremes, low, flat ships with three banks of oars) and arranged them side by side in two lines. Laid above each row of boats were two cables of flax and four cables of papyrus. These extremely heavy cables tied the boats together, and created the base of the deck.
