by Roma Agrawal
BUILT
For Maa,
and for little Samuel.
CONTENTS
Storey
Force
Fire
Clay
Metal
Rock
Sky
Earth
Hollow
Pure
Clean
Idol
Bridge
Dream
Acknowledgements
Sources
Photography credits
Index
A Note on the Author
STOREY
With one hand, I clutched my precious stuffed-toy cat, afraid that I would lose it. With the other, I clung to my mother’s skirt. Terrified and exhilarated by the new, strange, unknown world in constant motion around me, I held on to the only two things that felt familiar.
When I think of Manhattan now, I am always taken back to my first visit, as an impressionable toddler: the funny smell of the car exhausts, the shouts of the streetside lemonade vendors, the swarm of people rushing by, bumping into me unapologetically. It was an overwhelming experience for a child who lived far from the big city. Here, instead of open sky, I saw towers of glass and steel blocking out the sun. What were these monstrous things? How could I climb them? What did they look like from above? I turned my head left and right as my mother dragged me along the busy streets. Stumbling after her with my head raised, I was transfixed by these pillars that reached towards the clouds.
At home, with my miniature cranes, I stacked building blocks to recreate what I had seen. At school, I painted tall rectangles on big sheets of paper in bright, bold colours. New York became part of my mental landscape as I visited and revisited the place over the years, admiring new towers that appeared on the ever-changing skyline.
For a few years we lived in America, while my father worked as an electrical engineer. We didn’t live in one of the soaring skyscrapers that so impressed me on my visits to Manhattan, however, but in a creaking wooden house among the hills upstate. When I was six, my father gave up engineering to look after the family business in Mumbai, and I went to live in a seven-storey concrete tower that looked out towards the Arabian Sea. When my Barbie dolls finally arrived safe and sound at my new home, after a long sea journey in a storage container, it was of course essential that they were made comfortable. Pop helped me reassemble my cranes, laying out a large white sheet so I wouldn’t lose any pieces. Making loud, whirring noises, I lifted long plastic tubes and manoeuvred pieces of card into position, building a house for my dolls. My first step, perhaps, towards a career in engineering.
Having an American accent and – as you’ll soon discover if you haven’t already – a tendency to be a bit geeky, I found my new school a challenge at first. I was teased by some for being a ‘scholar’. But gradually I found friends and teachers that ‘got’ me. Through large gold-framed glasses, I eagerly read physics, maths and geography textbooks, and I loved art class, although I struggled with chemistry, history and languages. Mom, who had studied maths and science at university and had worked as a computer programmer, encouraged my growing interest in science and maths, assigning me extra homework and reading. Throughout my school years I loved these subjects best and I resolved to be an astronaut or an architect when I grew up. Back then, I’d never even heard the term ‘structural engineer’, and never imagined that one day I would play a part in designing a magnificent skyscraper – The Shard.
Since I loved learning so much, my family decided I should finish my schooling in another country, as it would be a great opportunity to broaden my horizons. And so, aged fifteen, I moved to London to study maths, physics and design at A level. Another new school in a new country, but this time I quickly sought out kindred spirits – girls who found Faraday’s law as fascinating as I did, and who experimented in the lab just for fun. Brilliant teachers paved my way to studying physics at university, and I moved to Oxford.
At school, physics made sense to me. At university, it didn’t – at least to begin with. Light was both a wave and a collection of particles? Space-time could be curved?? Time travel was mathematically possible?! I was hooked, but it was tough stuff to get my head around. Academically, I always felt like I was a few steps behind my peers. It was a real reward when I finally figured out how something worked. I balanced hours in the library with ballroom and Latin dance lessons, learning to wash clothes and to cook (though perhaps not all that skilfully, as you’ll see), and generally fending for myself. I was enjoying physics; my childhood dreams of going into space or becoming an architect became distant memories. At the same time, however, I had little idea of what I wanted to do with my life.
Then, one summer, I worked in the physics department at the University of Oxford, drawing up plans of all the fire-safety features in the various buildings. The task in itself was hardly world-changing, but the people who sat around me were working on projects that were. They were engineers, and their job was to design the equipment that physicists could use to seek out the particles that define how our world works. As you might imagine, I badgered them with questions and was astonished at what their jobs entailed. One was designing a metal holder for a glass lens – a simple task, you might think, except that the whole apparatus had to be cooled to -70° Celsius. Metal contracts more than glass, and unless the holder was cleverly and carefully designed, the cooling metal would crush the lens. It was just a tiny piece in a immense maze of machinery, but a complex and creative challenge. I spent hours of my free time trying to figure out how I might solve the problem.
Suddenly, it became very clear to me: I wanted to use physics and maths to solve practical problems and, in the process, help the world in some way. And it was at this point that my childhood love of skyscrapers re-emerged from the depths of my memory. I would be a structural engineer and design buildings. To make the transition from physicist to engineer, I studied at Imperial College London for a year, graduated, got a job – and began my life as an engineer.
As a structural engineer, I am responsible for making sure that the structures I design stand up. In the past decade I have worked on an amazing variety of constructions. I was part of the team that designed The Shard – the tallest tower in Western Europe – spending six years working out the sums for its open-air spire and foundations; I worked on a fancy footbridge in Newcastle, and the curving canopy at Crystal Palace station in London. I’ve designed hundreds of new apartments, brought a Georgian townhouse back to its former glory, and ensured an artist’s sculpture was stable. Whilst my job involves using maths and physics to create things (which in itself is incredible fun), it is also so much more. For a start, a modern engineering project is an enormous piece of teamwork. In the past, engineers like Vitruvius (who wrote the first treatise on architecture) or Brunelleschi (who built the breathtaking dome that crowns Florence’s cathedral) were known as master builders. They knew about every discipline necessary for construction. Nowadays structures are more complex and technically advanced, and no single person can design every aspect of a project. Each of us has an area of specialisation, and the challenge is to bring everybody together in an intricate and quietly frenetic dance that weaves together materials, physical effort and mathematical calculations. With the architects and other engineers, I brainstorm design problems. Our drawings assist site managers, and surveyors calculate costs and consider logistics. Workers on site receive materials and reshape them to create our vision. At times, it’s hard to imagine that all this sometimes chaotic activity will resolve into a solid structure that will last for decades, or even centuries.
For me, each new structure I design becomes personal, as ‘my’ building grows and takes on its own individual character. At first we communicate through a few rough drawings, but gradually I
discover what will prop it up, and how it will stand tall and be able to evolve with the changing times. The more time I spend with it, the more I come to respect, even love it. Once complete, I get to meet her in person, and walk around her. Even after that, as far as I’m concerned, we have an ongoing commitment to one another, and I watch from afar as other people take my place and develop their own relationships with my creation, making the building their home or workplace, protected from the outside world.
Of course, my feelings for the structures I have worked on are particularly personal, but in fact all of us are intimately connected to the engineering that surrounds us – the streets we walk on, the tunnels we rush through, the bridges we cross. We use them to make our lives easier, and we look after them. In return, they become a silent but crucial part of our existence. We feel charged and professional when we walk into a glass skyscraper with neat rows of desks. The speed of our journey is emphasised by steel rings flying past the windows of an underground train. Uneven brick walls and cobbled stone pathways remind us of the past, of the history that has gone before us. Structures shape and sustain our lives and provide the canvas of our existence. We often ignore or are unaware of them, but structures have stories. The tense cables stretching above a massive bridge across a river; the steel skeleton beneath the glass skin of a tall tower; the conduits and tunnels burrowing beneath our feet – these things make up our built world, and they reveal a lot about human ingenuity, as well as our interactions with each other, and with Nature. Our ever-changing, engineered universe is a narrative full of stories and secrets that, if you have the ears to listen, and the eyes to see, is fascinating to experience.
My hope is that, through this book, you too will discover these stories and learn these secrets. That a new understanding of our surroundings will change the way you look at the hundreds of structures you move over, below and through every day. That you will see your home, your city, town or village, and the countryside beyond with a new sense of wonder. That you will see your world through different eyes – the eyes of an engineer.
FORCE
It’s a peculiar feeling when you step onto or into something you’ve designed. My first project after leaving university was the Northumbria University Footbridge in Newcastle, England. For two years, I worked with the architects’ plans, helping to make their vision a reality, covering hundreds of pages with calculations and creating countless computer models. Eventually it was constructed. Once the cranes and diggers had moved on, I finally had the opportunity to stand on the steel structure I had helped to create.
The Northumbria University Footbridge, built in 2007 to link the two main sites of the university in Newcastle Upon Tyne, England.
Briefly, I stood on the solid ground just in front of the bridge, before taking a step forward. I remember that moment: I was excited but I also felt disbelief – amazed that I had played a role in making this beautiful bridge stand, so that hundreds of people could walk across it every day. I looked up at its tall steel mast and the cables radiating from it, supporting the slim deck safely above the motorway traffic – it held its own weight, and mine, effortlessly. Balustrades, carefully angled to make them difficult to climb, reflected the cold sunlight. Below me, cars and trucks whizzed past, oblivious to this young engineer standing proudly on ‘her’ bridge, marvelling at her first physical contribution to the world.
Standing upon the Northumbria University Footbridge, my first project as an engineer.
It was, of course, steadfast beneath my feet. After all, those numbers and models I had carefully executed to calculate the forces my bridge would be subjected to had been checked and re-checked. Because, as engineers, we can’t afford to make mistakes. I’m conscious that every day thousands of people will use structures that I have designed: they will cross them, work in them, live in them, oblivious to any concern that my creations could let them down. We put our faith and our feet (often quite literally) on engineering, and it is the engineer’s responsibility to render things robust and reliable. For all that, history has shown us that things can go wrong. On the afternoon of 29 August 1907 residents of Quebec City thought they had just been shaken by an earthquake. In fact, 15km away, something far more unthinkable was happening. On the banks of the Saint Lawrence River the sound of ripping metal tore through the air. The rivets that held together a bridge under construction had snapped, catapulting over the heads of terrified workers. The steel supports for the structure folded as if they were made from paper, and the bridge – with most of its builders – plunged into the river. One of the worst bridge collapses in history, it is a brutal example of how mismanagement and miscalculation can end in disaster.
*
Bridges expand cities, bring people together and promote commerce and communication. The idea of building a bridge across the Saint Lawrence had been debated in parliament since the 1850s. The technical challenge, though, was huge: the river was three kilometres wide at its narrowest point, with deep, fast-moving water. In winter the water froze, creating piles of ice as high as 15m in the river channel. Nonetheless, the Quebec Bridge Company was eventually set up to undertake the project, and work on the foundations began in 1900.
The company’s chief engineer, Edward Hoare, had never before worked on a bridge longer than 90m (even the original plans for this project called for a ‘clear span length’ – i.e. a length of bridge without any supports – of just over 480m). So the fateful decision was made to enlist the services of Theodore Cooper as consultant. Cooper was widely regarded as one of the best bridge builders in America, and had written an award-winning paper on the use of steel in railway bridges. Theoretically he must have seemed like the ideal candidate. But there were problems from the start. Cooper lived far away in New York, and his ill health meant he rarely visited the site. Yet he insisted on being personally responsible for inspecting the steel fabrication and construction. He refused to have his design checked by anyone and relied on his relatively inexperienced inspector, Norman McLure, to keep him informed of progress on site. Construction on the steel structure began in 1905, but over the next two years McLure became increasingly worried about how the build was progressing. For a start, the pieces of steel arriving from the factory were heavier than he expected. Some of them were even bowed rather than straight because they were buckling under their own weight. Even more worryingly, many of the steel pieces installed by the workers had already deformed even before the bridge was complete, a sign that they were not strong enough to carry the forces flowing through them.
This deformation was the result of Cooper’s decision to change the design of the bridge away from its original plans, increasing the length of the central span (the unsupported middle of the bridge) to nearly 549m. Ambition may have clouded Cooper’s judgement: in making the decision he might have hoped to become the engineer responsible for the longest-spanning cantilever bridge in the world, an honour held at the time by the Forth Bridge in Scotland. The larger the span of a bridge, the more material you need to build it, and the heavier it becomes. Cooper’s new design was about 18 per cent heavier than the original, yet without paying enough attention to the calculations, he decided that the structure was still strong enough to carry this extra weight. McLure disagreed, and the two men argued about it in an exchange of letters. But nothing was resolved.
Finally, McLure became so concerned that he suspended construction and set off by train to New York to confront Cooper. In his absence, an engineer on site overturned his instructions and the workforce went back to assembling the bridge, with tragic results. In just fifteen seconds, the entire south half of the bridge – 19,000 tonnes of steel – collapsed into the river, killing 75 of the 86 people working on the structure.
The scene of devastation following the collapse during construction of the Quebec Bridge in 1907, spanning the Saint Lawrence River, Quebec City, Canada.
Many problems and mistakes contributed to the bridge’s collapse. In particular, the disaster reveale
d the dangers of putting huge power in the hands of one engineer without supervision. In Canada and elsewhere, organisations of professional engineers were set up to regulate the profession and try and prevent a repeat of the Quebec Bridge mistakes. Ultimately, however, much of the responsibility lies with Theodore Cooper, who underestimated the weight of the bridge. In the end, the way it was engineered meant it was just too feeble to hold itself up.
*
The abrupt devastation of the Quebec Bridge demonstrates the catastrophic effect gravity can have on a faulty human construction. A major part of the engineer’s job is figuring out how structures can withstand the manifold forces determined to push, pull, shake, twist, squash, bend, rend, split, snap or tear them apart. Grappling with gravity is therefore a key consideration on many projects. It is the omnipresent force that holds the solar system together, and which attracts everything on our planet towards its centre. This creates a force within every object, which we call its weight. This force flows through the object. Think about the weight of different parts of your body. The weight of your hand acts on your arm, pulling on your shoulder then pushing into your spine. Flowing down the spine, the force reaches your hips, and here, at the pelvic bone, the force splits into two, flowing into each of your legs and down into the ground. In much the same way, if you build a tower from straws and pour water on top of it, the water will stream through the different pathways it finds, dividing where more than one option is available.
When planning a structure, then, it is vital for an engineer to understand where the force is flowing, what kind of force it is, and then make sure that the structure transmitting the force is strong enough for the job.
There are two main types of forces that gravity (and also other phenomena such as wind and earthquakes) creates in structures: compression and tension. If you roll a piece of thick paper into a cylindrical tube, stand it vertically on a table, and then put a book on top of it, the book pushes down on the tube. The force with which it does this (which is its weight multiplied by gravity) flows through the tube down to the table – just as your weight flows through your leg. The tube (like your leg) is in compression.
