Book Post : 25
Book Name : Built : The hidden stories behind our structures
Author : Roma Agrawal
How I came to read it : Found this book while randomly scrolling through the library shelves.
Did I like it? : Yes, absolutely. This is one of the finest books on engineering I have read. Roma makes it an easy read. There are no complicated descriptions or math anywhere though personally I wouldn't mind if they were included. The love Roma has for her subject can be clearly seen. And best part is she looks at the past to explain many of the themes she explores. Ranging from the Persians, Romans and Harappans she visits many famous builders of the past. I am a fan of history so this was something that I loved. There are also many personal anecdotes which gives the book a nice personal touch. In places where she is explaining any concepts there are hand drawn illustrations which gives the feeling of being present in a classroom. She almost takes a teacher like stance while explaining some of the concepts adding to the classroom feeling.
Top 10 things I learned from this book:
1. There are 3 ways in which wind can affect a structure. One, wind can topple a structure if its light. Two, wind can cause a building to sink into the ground if the ground is weak. Third, wind can make a structure sway like a boat rocking at sea.
2. The Romans were master builders. They had a very good understanding of the concepts involved in building big structures. Marcus Vitruvius Pollio who was born in 80 BC is sometimes called the 'the first architect'. He wrote a hugely influential ten volume treatise on the design of structures called De Architectura.
3. Emily Warren Roebling was engineer who worked on the building of Brooklyn Bridge in the 1870s. In a profession dominated by men she made a mark for herself. Her husband was the Chief Engineer of the project but got bed ridden when he developed the Caisson's disease during the construction. She served as the liaison and supervisor of the construction communicating between her husband and the on site personnel. But slowly over the duration of the project she took on a more authoritative role and influenced many decisions. She was technically brilliant and was held in high esteem by all who worked with her.
4. Every building has a core. It can be a concrete core or a steel core. A core is at the centre of the building and is usually well hidden. They usually house essential services like elevators, stairs, ventilation ducts etc.
5. Taipei 101, which was at one time the tallest building in the world has a massive pendulum housed in some of its top floors. Weighing a massive 660 tonnes, it is the heaviest pendulum in a skyscraper anywhere in the world. The purpose of this ball is to damp the vibrations produced in the building during earthquakes or high winds. It absorbs the energy created by the movement of the building and avoids resonance. In August 2015 Taiwan was stuck by a typhoon which had winds blowing at around 170 km/h but Taipei 101 was unaffected because of the pendulum which recorded movement up to 1 m, which is its largest movement ever recorded.
6. Fazlur Khan, a structural engineer from Dhaka, Bangladesh came up with the brilliant innovation of putting a building's stability system on the outside. Kahn created a external skeleton using large prieces of diagonal bracing to form triangles. This system is called Tubular system and it has been used in many famous buildings around the world including in Burj Khalifa which uses a variation of Fazlur's innovation. He is called the 'father of tubular designs for skyscrapers'.
7. There is mention of one of my famous engineers, Isambard Kingdom Brunel (I like him for his inventions in the areas of railways and ships). He played an important part in building the tunnel below the river Thames (1825 to 1843). His father Marc Brunel was the Chief Engineer on this project. Marc invented the first tunneling shield which was an ingenious invention. He was inspired by the actions of a ship worm called Teredo Navalis. This worm, with the help of its horns on the top of its head, powdered the wood in front of it and ate it ast it moved forward. It then excreted this digested mixture behind it, which lined the tunnel it just created, shoring it up. This created a strong passageway behind it as it moved forward.
8. When did humans started building sky scrapers? What happened that allowed us to build those tall structures? The answer to this question is Henry Bessemer. Before Henry we did not have materials strong enough to withstand both compression and tension. The materials used earlier like bricks and mortar are good in compression but not in tensions (when pulled apart). Steel, which is simply Iron with 0.2% Carbon content, was perfect. It was good at both compression and tension. But at that time it was very expensive to manufacture. Henry Bessemer, in 1856, solved this problem with his use of a closed furnace with warm air running through it. His method was a huge step and mass manufacture of steel started off. This lead to massive expansion of the railway networks and humans started to build skyscrapers.
9. The idea of reinforcing concrete with metal started with a man who was fed up of his clay pots cracking up. Joseph Monier, a French gardener in the 1860s was frustrated seeing his clay pots constantly cracking so he tried making them with concrete. Those cracked too. He then randomly added a metal grill to the concrete. This solved the problem. Metals are good in tension, concrete is not. By combining these two materials Monier created a perfect combo. Steel reinforcement is a common way of building today.
10. Romans built the world's first apartment buildings. These were called Insulae and sometimes they reached 10 storeys tall which was a first at that time. By AD 300 the majority of Rome's population lived in Insulae which numbered over 45,000 in the city whereas normal single family homes were around 2000.
There are many more interesting concepts and facts in the book. Read it to find out more!
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