More Industrial Revelations Europe E05 Eiffels Tower

in 1889 this was the tallest building in the world 300 meters high and designed to celebrate the centenary of the French Revolution but what is the connection between this incredible structure and this a humble cooking pot this is still the world’s most famous iron tower it’s a masterpiece of engineering the combination of two hundred years of development in the iron industry the story of how Eiffel Tower came to be built takes us back to the early 18th century in Eiland for thousands of years blacksmiths had bashed white-hot iron into shape to make small everyday objects like horseshoes blacksmiths we’re working with a very pure kind of iron was called wrought iron it was produced by smelting iron ore in a furnace fueled with charcoal made from trees you could bang it you could bend it and it wouldn’t break that was fine for horseshoes but this was piece work a long way from the high volume must production of iron parts that Eiffel would demand for his tower what was needed was an industrial revolution and it was here in structure in the English Midlands where it all began today this is a peaceful Valley but in the early 1700s it would have been filled with smoke and the roar of charcoal furnaces producing molten iron business was booming but they had a problem there’s a law in the hills around here and wood for charcoal but it was crazy you needed two hundred and fifty kilograms of timber to make only fifty kilograms of charcoal imagine how many trees it took to fuel one of these furnaces if the iron industry was to grow someone had to solve the fuel crisis then in 1708 an English metal worker Abraham Darby came to Shropshire to carry out some secret experiments and this is where the cooking pot ends us the story table he wanted to must produce pots like these and cast them in sand he had seen the technique used by brass workers in Holland clever people is that before we could start casting his pots Darby had to find a new fuel to mass-produce iron in his furnace all the raw materials were loaded in from up here this here is the charging hole that because charcoal was so hard to make in large quantities Dhar we wanted to find an alternative fuel and this is what he came up with coke the original smokeless fuel with the coke he could fire the furnace up to 1,200 degrees Celsius there was an unlimited supply of it because it was made by heating coal to drive out gas and impurities just up the valley from Darby’s old furnace they are still using coke to produce iron for casting this furnace is a rare survivor from the 19th century now the furnace is different but the principle is the same get it hot get it charged and the molten metal runs off at the bottom today’s charge just like in Darby’s day it’s coke here limestone and because we don’t have iron ore we use scrub on base be any target I really let’s get it in everything is thrown in together the limestone is added to help the iron flow bringing any impurities to the surface so that they can be tapped off as slag da we have got his molten metal but to mass-produce his pots he had to master the art of casting iron in samples time for me to make one first of all you need a wooden pattern that’s the shape of the thing you want to cast in iron later on now there isn’t so much demand for cooking pots nowadays so I’m gonna make an anvil today and this is the mold I’m

gonna put the sand in around the anvil all the sand needs to be really really fine so that you don’t get lumps around it this isn’t any old sand it’s fascial sand made of small particles so it holds its shape when you pack it in it’s black because it’s mixed with coal dust to stop it sticking to the pattern there you are that’s the shape that’s great wonderful time to fill it with hot metal hot yep you better believe it the cast iron from Darby’s coke fired furnace wasn’t as pure as the wrought iron blacksmiths were working with but it was perfect for pouring into sand molds and soon Darby was producing five and a half tons of iron a week that’s a lot of cookie pots but what about my anvil this is the moment of truth we’re gonna see the result of my work wow this is great I mean this may look simple but in Darby’s day this type of mass production was revolutionary but we’re still a long way from Eiffel and it’s 300 meter tower casting like this started a new Iron Age and it made the Derby family a fortune two generations later they made another breakthrough it was Darby’s grandson Abram Darwin a third who took iron into the construction business in 1777 he won a contract to build a bridge across the river seven now he wanted to make a showcase to promote the family firm so he decided to build this the world’s first iron bridge just up the river at the Derby works they had become experts in casting iron so why not cast parts for a bridge but the sheer scale was massive the bridge has a span of 30 metres the biggest ribs weigh over five tons each and amazingly it all slots together they couldn’t use rivets they hadn’t been invented so they used carpentry techniques the rips are all fastened with dovetail joints it may look old-fashioned now but this bridge changed the world it was so famous that the place itself became known as ein bridge it took Darby a couple of years to build the bridge and it cost him twice as much as he had planned but it was soon paying its way this is were coming from all over the country and they all had to pay at all to cross the bridge the Ironbridge inspired engineers around the world to start using car sign for construction and with the coming up the railways the demand for bridges was booming for bridge builders everywhere car sign had some big advantages because once you had a patent for one of the ribs he could make as many as you like this is bonus Willy it’s one of the last surviving cast iron bridges in Paris and that is because cast iron does have its downside it’s five times stronger in compression than it is in tension and that is fine as long as the weight presses down directly from above or when it’s in an arch so that the force is directed to the side abutments but now if you have longer des with a lot of tension on them they could easily break and then the whole bridge could collapse Carsten is brittle and if you put a piece under the microscope you can see why the white is pure iron but the black and brown specks are impurities like carbon and phosphorous making it much more likely to break an attention now what was needed was a type of vine that could take the strain that wouldn’t break my cast iron it had existed all along wrought iron wrought iron has a completely different structure to car stein there’s hardly any carbon and the molecules of iron run in lines making it more flexible and less likely to snap on the stress this pure iron which had been used by blacksmiths for centuries couldn’t be must reduced straight from Darby’s coke fire blast furnaces the breakthrough came with a completely new furnace and the technique called puddling back in 1784 an englishman henry chord had designed a special type

of furnace that could convert large quantities of Castine into the much pure raw time this is it what this one has seen better days but you can still see how it works this is where they lit the fire and then hot gases were drawn through the furnace up the chimney here is the clever part the iron was loaded in here away from the fire hot gases passed over the top melting the metal but there was never direct contact no contamination for the second stage you need it one of these a puddling rod it’s used to stir the molten metal keeping it in contact with the air cold found out that if he kept stirring the molten metal impurities like carbon and sulfur combined with the oxygen and burned off and what you were left with was a spongy mass of pure iron that could then be bashed under a huge hammer this steam hammer could do the work of a hundred blacksmith wrought iron was now available on a commercial scale with this iron produced by the public process engineer skid now built massive structures that have never been possible before like this the Austerlitz railway station in Paris these were like great cathedrals for the railway Age bright and airy and revolutionary for their day and to cover all the lines and to protect the passengers the roof had to be very wide and that didn’t a lot of light all technology couldn’t do it the answer was to combine the two types of iron cast iron for the supports once they had them balled they could cast each one the same and resting on top of them was an intricate web of wrought iron beams and ties building with iron on this scale was inspiring one French railway engineer Gustave Eiffel he was already making a name for himself constructing bridges out of high-quality wrought iron that was the iron that Eiffel would recommend when the call came for a world meeting 300 meter tower to be built in a center of Paris in May 1886 the city of Paris was planning a Great Exhibition to celebrate the centenary of the French Revolution and to demonstrate the best of French technology for their showpiece they wanted to be the first in the world to build a tower 300 meters high out of iron but it wasn’t a new idea for some time – vitals colleagues had been dreaming of building such a tower so when the city of Paris put out the call for a design eiffel was ready he used his team’s original ideas eiffel a nice team proposed building a tower with full legs standing apart at the base exactly on the points of the compass north east south and west coming together at the top and joined by metal dresses just five years earlier eiffel had built what was then the world’s highest bridge negara be railway viaduct in central France crossing a Gorge over a hundred metres deep he took iron construction techniques to a new level with this achievement behind him it was not surprising he won the Paris competition but now he personally had to raise most of the 8 million francs to build the tower and he and his team of hard bridge builders only had two years to make it if he compared the bridge it gotta be with the tower you can see a remarkable similarity they are both massive structures but they appear light and airy it is no coincidence I feel used very similar engineering techniques that were incredibly cost effective in their use of iron one of the earliest wrought iron bridges in Wales had used a giant box girder made of iron sheets a bit like this actually in reality of course it was a bit longer 460 meters to be precise it did the job it was a very expensive use of iron Eiffel wanted to

make his girders with cross pieces but a rectangular shape would be too weak it could easily shift well so his solution was to make his girders with equilateral triangles like this you make a very strong structure with it and see it won’t budge and it needed to be strong because a 300 meter tower would be very vulnerable to high winds just 10 years earlier that had been a catastrophic disaster in Scotland when the iron railway bridge over the River Tay collapsed during a fierce Gale eiffel’s tower was going to be a showcase for French engineering he couldn’t afford to make mistakes once again the solution was in his use of open Gerdes to assemble his Tower Eiffel needed thousands of precision paths made of wrought iron fortunately the technology to produce them have been developed some 80 years earlier by the iron master Henry Court don’t let this tranquil Valley here in East of France fool you we are talking heavy industry here this water used to provide power for the force disarm right behind me where quartz brilliant system of turning iron bars into quartz for construction was used as far back as 1810 these buildings contain the last rolling mill of its type still in everyday use in Europe the raw material is now steel not iron but the technique is the same passing these bars through sets of grooved rollers produces a precise profile Eiffel would have used this kind of technology to make the 18,000 individual parts needed for this iron tower the journey from drawing board to finished part begins with a white-hot iron bar in a furnace the gates of hell are open and the metal bar inside this furnace it’s got to a precise place and then eat it to the staggering 1,200 degrees whoo this bar is really too hot to handle but it is exactly the right temperature for rolling nothing has really changed here ever since the 1880s except for one thing McDaniel they would have used a water wheel to drive these rollers and now they use an electric motor the ideas the bars gradually squeezed each time it goes through the rollers to make the cross-section smaller and the bar even longer they can get up to 12 metres long it was like a giant 3d jigsaw puzzle and everyday iron parts were delivered down below they were hauled up by mobile cranes that were attached on the inside of the legs the mobile cranes would travel up as it got higher and higher it is said that the 3-ton girdle was raised into position in just 20 minutes one of the trickiest stages was to align the massive giris to reach the first platform at almost 60 meters at the right angle so that the platform was exactly level each of the four legs was placed on concrete and stone foundations you can see here they were angled at the surface to meet the girders at the right angle eiffel was able to make my nude adjustments to the angle of each girder using a clever hydraulic jack a bit like jacking a car up in a modern garage where they used car sign to take the weight remember cast-iron was very strong in compression these things take the weight of the entire Tower in March 1888 less than a year after building began Eiffel successfully completed the first platform but there was still over 200 meters to go the Parisians were astonished at the speed the tower was going up and at the small number of workers at any one time there could be as few as 80 riveters at work but they were banging in more than 1500 white-hot rivets a day not one of eiffels workers died during construction of the tower and that is amazing if you look at the height at which these people had to work that is if you don’t count this poor guy who’s trying to show off to his girlfriend one evening and fell

off Eiffel completed his tower in two years two months and five days it was an extraordinary feat of Engineering now he would have to make it pay his initial contract was just for two years to make his money back he’d have to get massive numbers of paying visitors to travel up his tower and that meant lived the first public lift had been installed in America just 30 years before in 1857 but eiffel’s tower with its inclined legs and potentially a huge number of visitors was a unique challenge the solution was to use hydraulic energy to power the lifts it works like this water is pumped under high pressure into these massive cylinders they are connected to a piston and trolley which is connected by cables to the lift carriage when the cylinders come down the piston and trolley moved back and the lift carriage is pulled by cable up to tower and with a little bit of help of modern technology it’s still being used today this lift is over a hundred years old his lips carried two million visitors in the first year and within two years he had covered the cost of the tower the tower made Eiffel a household name he became known as the iron magician since 1889 220 million people have admired his creation iron has come a long way since Abraham Darby and his cooking pot