1 2 3 Our goal in this lecture will be to show how the definition and ideas of structural art began and to do that we need to turn our attention to Great Britain and the first civil engineers that developed following the industrial revolution. So we look at a series of structures starting at the onset of the industrial revolution. And we also continue defining structural art through comparative critical analysis which makes a comparison based on the 3 perspectives of structural art: scientific, social, and symbolic. 4 SLIDE 2 Image: Public Domain CIA World Facebook (https://commons.wikimedia.org/wiki/File:Uk-map.png) To begin we have to look at the beginning of the fundamental changes that happened as a result of the industrial revolution. I’m not going to go deep into the Industrial Revolution, but there were two major changes that led to the emergence of this new art form of the engineer. One is the change of building material. For example, they were building with wood and stone, and then following the Industrial Revolution, constructions are made with iron. There is also a change of power source from animal and human power to steam power. These two fundamental changes enabled the materials iron, steel and concrete, etc. to come about. Our lecture today is going to focus on engineering in Great Britain. Today’s lecture focuses on designers of Great Britain [Indicate Scotland, England, and Wales on map] Industrial revolution began in Great Britain in late 18th century on basis of two fundamental changes in engineering: 1 – change of building material from wood and stone to industrial iron This was THE material of the industrial revolution 5 2 – steam power (instead of human or animal power) – made iron possible (but we don’t focus on this point in this class) What also happened was that this new material was so much stronger that it needed less and less material. That meant a potential danger – failure. This lead to modern engineering and modern engineering schools where students began to be trained rigorously in modern engineering. 5 SLIDE 4 Image: Wikipedia commons (https://commons.wikimedia.org/wiki/File:Stonehenge,_Salisbury_retouched.jpg) Stone Henge: We’ve seen this before. Stone – small spans because weak in tension. 6 SLIDE 5 Image: Public Domain For the purposes of this lecture, we’ll say that the Industrial Revolution began here with the construction of the Iron Bridge. Remember we were spanning about 10 ft with the stone at Stone Henge, now we’re spanning 100 ft with iron and this is built by Abraham Darby III. We will revisit this bridge and make an analysis. New material – the Iron Bridge versus Stone Henge – much longer spans now possible -Iron Bridge is also in Britian, over Severn River -First real structure that appears out of this new material -Completed in 1779 -For the purposes of this course, the date for the industrial revolution is 1779 because it is the first time that a structure has been built out of metal. -It still stands today as a monument for metal structures. 7 Let’s look at these metal bridges from these three perspectives. You’ll see this over and over again as metrics to study structures. One is the scientific perspective and in this case, it applies to the new material of iron. From the social perspective, we have a new opportunity from industrialization. From a symbolic perspective, we have a new way of designing and finding forms in particular bridges which we will look at today, and we call that structural art. -Taking our three part perspective: [read slide] -Industrialization changes society -All 3 begin at same time: late 18th / early 19th century. 8 Let’s look at the scientific point of view, which focuses on the material iron. Iron is stronger than wood or stone and you need less material to carry the same amount of load. So iron has 30,000 psi capacity where stone may have 3,000 psi capacity. Iron is more permanent than wood because it corrodes, so it does require maintenance. It permits forms that are lighter because it is a stronger material as said previously. Look at scientific perspective, we recall that iron is much stronger than stone: Stone = 3000 psi Iron = 30,000 psi (10 x stronger) Iron is more permanent than wood but not more permanent than stone because iron corrodes and not good in fire Permits forms lighter than those of stone, even though iron is denser. But because it is so strong, use much less material. Iron Bridge built by Abraham Darby III from cast iron pieces 9 SLIDE 8 Image: Flickr by Bs0u10e0, https://www.flickr.com/photos/51939258@N00/6922612520 The iron bridge was actually built as an advertisement, it’s interesting. When Darby built the bridge, it was to advertise his company that was making pots and pants out of iron. This bridge was essentially a huge billboard for his company. If we look at it carefully, we see that is is made up of several arches. It was also used by Darby’s (the ironmakers) as an advertisement. Darby’s were in business for building pots, pans, weapons. Used the Iron Bridge as visible advertisement to show how iron can span 100ft between supports 100 ft in span – a lot for those days (today not much) 10 SLIDE 9 Image Left: Flickr by Elliott Brown, https://www.flickr.com/photos/ell-r- brown/3815844332/in/pool-iron_bridge/ Image Right: Elizabeth Billington-Fox Here we see the cross-section with five arches. Looking close up at this bridge, we see that it’s copy wood construction. It’s copying the connections of wood. So Abraham Darby uses what he knows from wood construction and applying it to an iron bridge. We’re going to come back and make a critique of this bridge in comparison to another bridge later on, but the significance of this bridge is that it’s the first cast iron bridge. -Inside of the bridge -1st cast iron bridge 11 -Shows details of it -5 arches -Very light compared to others of the time -Built out of a way that is made to look like a wooden structure (carpentry in iron) -Model is mortise and tendon (connections) -Now we look at the social aspect of these British metal forms -Begins with Queen Elizabeth one. 12 Image (left): By maarjaara (originally posted to Flickr as Roman bridge) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons; Roman Bridge, Vaison-la-Romaine, France. Pic 02.jpg Image (right): David Evans / Flickr flic.kr/p/94sNP6 Let’s see how much you guys have been listening. Here’s two bridges one made of stone and one made of iron on the right. As I mentioned, we have a density of the iron as about three times larger than that of stone. My question is which bridge is going to weigh more. 13 Which bridge weighs more? https://www.polleverywhere.com/multiple_choice_polls/XdgnQvuGMjx58oc 14 Image: http://www.bl.uk/onlinegallery/onlineex/kinggeorge/t/003ktop00000012u036b0001.html A stone bridge will be heavier than the cast iron bridge. Explanation: although cast iron is heavier than stone by volume, it is also much stronger than stone. Therefore, one can use much less material to build an arch. The resulting iron arch is much lighter than a stone arch. For example, for the bridge built by Rowland Burdon Esq., MP, over the River Wear at Sunderland. An iron arch was estimated to be 15 times lighter than a stone arch of a similar size 15 To summarize, iron may be denser than stone but is stronger and thus requires less material for the same strength. This allows the structures built with iron to be thinner and more transparent, and gives rise to this new aesthetic of “transparency” in structures in contrast to the bulkiness of stone construction. From the social point of view, we have industrial revolution. Queen Elizabeth outlaws woodcutting which was used for fuel and construction. People then needed to find an alternative source of fuel. So they looked underground and found coal. Then there was British Democracy that encouraged free enterprise. There were not many rivers or modes of transportation connecting the major cities in Great Britain, so there was some autonomy in each of the cities of what was done. Great Britain’s isolation from the mainland of Europe spared the country some political stability. All of these factors including the Industrial Revolution enabled Great Britain to be the first to design these structures from the new materials. -A -Queen Elizabeth – forests in GB getting diluted -She outlawed wood cutting -Wood used for fuel and construction, needed to control this -Looked underground and found coal 16 -New material needed for building & fuel -B -Britain was not really run from London. Transportation system in GB was bad. Tendency for local freedom in what was done. -London was far from west midlands and left them alone – that kind of democracy encouraged free enterprise (all did not come from London) -C -Island isolation provides political stability. Avoided wars on continental Europe. Never been invaded since 1066 therefore sense of security. -This is not a course in political philosophy (nor the history of such things), but touches upon points relevant to our study 16 SLIDE 12 Image: http://www.bl.uk/onlinegallery/onlineex/kinggeorge/t/003ktop00000012u036b0001.html -Key person is Thomas Telford – born in Scotland in 1757 -Most famous structural engineer of his era -Brought up in poverty -Worked since the age of 8 – began his career as a stone mason -In 1782 (25 yrs old) left for London where he worked as a draftsman in an architect’s office -In 1787 as a county surveyor he designed his first bridge (3 stone arch spans) completed in 1792 -Began to be recognized for his masonry arch bridges -Learned his trades as an apprentice 17 Something happened that change Telford’s way of thinking about bridge design.