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

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4 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

5 SLIDE 2 Image: Public Domain CIA World Facebook ( 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 18 th 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

6 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

7 SLIDE 4 Image: Wikipedia commons ( Stone Henge: We ve seen this before. Stone small spans because weak in tension. 6

8 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 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

9 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 18 th / early 19 th century. 8

10 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

11 SLIDE 8 Image: Flickr by Bs0u10e0, 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

12 SLIDE 9 Image Left: Flickr by Elliott Brown, 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 -1 st cast iron bridge 11

13 -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

14 Image (left): By maarjaara (originally posted to Flickr as Roman bridge) [CC 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

15 Which bridge weighs more? 14

16 Image: 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

17 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

18 -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

19 SLIDE 12 Image: -Key person is Thomas Telford born in Scotland in 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 Began to be recognized for his masonry arch bridges -Learned his trades as an apprentice 17

20 Something happened that change Telford s way of thinking about bridge design. There was a big flood in the Severn River (where the Iron Bridge was built). The waters rose and ran quite hard, and the wood bridges were lifted up and floated away. Then the heavy stone bridges acted as dams, and the water pressure ended up knocking over the stone bridges. The only bridge that survived was the iron bridge and Telford saw this. The reason why it wasn t harmed was because it was strong and transparent so the water was flowing through the bridge. This left an impression on Telford and he redirected his design towards iron bridges switched from architecture to engineering big flood, took out all bridges except Iron Bridge -(stone bridges acted as dams and pushed, wood bridges were lifted up) -Iron bridge was light enough so water can go through it and anchored down. -When Telford saw this he was impressed and turned his attention from masonry to iron SLIDE 13 Image: David Evans / Flickr flic.kr/p/94snp6 18

21 SLIDE 14 Image: Bracegirdle and Miles, pg. 19 One of this first bridges he designed is this one here, which is no longer standing due to the difficulty of maintaining it. It was about 130 ft span, about the same span of the iron bridge. This is what we call an ambiguous bridge. We have two arches, essentially copying the forms we ve seen in wood. It s ambiguous because we don t know which arch is carrying the load. An important factor in our critique of structures is the transparency of how the loads are being carried. -Saw an opportunity in Britain to build bridges and canals (infrastructure for I.R) -Bildwas bridge 1 st bridge of iron, not a very good work of structural art -Because two arches and don t know which is carrying the load -Copied after wood arches -½ engineered, ½ craftsman design -Built over Severn River 19

22 Here are some other works. Keep in mind we are only dealing with ft spans here, which at the time were considered long spans. -Telford early works after began studying bridges these three are major ones -LLangolen (Welsh bridge) got commission in Bonar (Scottish bridge) beginning of mature designs of Telford does not exist taken down (for reasons not connected to design) -T&B p.31 Telford s iron bridges were not the only such works at this time, nor were they the longest spanning ones. John Rennie Telford s only rival as Britain s finest bridge designer of the period designed iron bridges on the order of 200 ft. But what set Telford apart is his distinct personal style; his iron arches are more visually attractive and they are also technically superior A recent compilation of cast iron bridges built between 1779 and 1871 lists the bridges in order of their technical quality. Of the top 9 listed, 8 are Telford s. Of those 8, 5 are still standing today 20

23 SLIDE 16 Image: Telford s autobiography The Bonar bridge is an arch bridge, and you can see a lattice structure here. An important aspect of this bridge is the way Telford spoke about it. -Drawing of Bonar bridge comes from autobiography of his book. -Cast iron - His design criteria for this bridge were essentially efficiency, economy, and elegance - You can read his exact words in the Tower and the Bridge (page 31) where you will see that he is thinking like a structural artist as we define it. -Bridge was taken down after 90 years (not for defect but hard to maintain) -Similar to Craigellache 21

24 When Telford spoke about it s design, he mentioned the criteria as the following quote. 22

25 This aspect highlighted is indicative of considering the efficiency of the bridge. Remember that efficiency is not using more material than is needed, after considering safety factors. 23

26 Remember how tightly economy and and construction go together. 24

27 Finally he speaks about appearance which alludes to elegance. Telford doesn t say the word structural art, but this is the spirit through which he is going about designing his work. 25

28 So here is a bridge in Whales. This bridge is still standing today and this is a new form for aqueducts at the time which were very important. It was important for these aqueducts to connect cities in Great Britain. The Pontcysyllte Aqueduct carries the Llangollen Canal over the valley of the River Dee in north east Wales. Completed in 1805, it is the longest and highest aqueduct in Britain viaducts were important to connect cities in GB SLIDE 17 Image: public domain (wikimedia commons and flickr) 26

29 SLIDE 18 Image: Hadfield, Charles. The Canal Age. Pg. 25 The cities were essentially isolated from one another in Great Britain, with a lack of continuous main waterways. This isolation led to the free enterprise that was mentioned earlier. -Industrial Revolution required transportation -Pre industrial revolution map of Britain -See lines of rivers -Not many so not good for transportation; no main waterways - Birmingham & Manchester = great industrial cities but isolated, therefore lots of canal building (can t go up and down) 27

30 SLIDE 19 Image: Hadfield, Charles. The Canal Age. Pg years later major canals were built connecting major cities -Previous aqueduct was an example of a manmade waterway to connect the cities -Beginning to show engineering works - Birmingham becomes center of connections -Network is growing connecting cities 28

31 SLIDE 20 Image: By G.F. Yates [Public domain or Public domain], via Wikimedia Commons -Barton Viaduct on right (1760) = what was done before Ind. Revolution. Everything = wind/human/animal power -Barton = arch form, pre industrial revolution, stone bridge with Roman form; boat being pulled by horses -These are the kind of aqueducts prior to what Telford would design -Watercolour, pen and ink image of James Brindley's Barton Aqueduct circa 1793 carrying the Bridgewater Canal over the River Irwell. Horsedrawn barge moving across the aqueduct, small river barge beneath 29

32 -Llangollen Iron -Llangollen = much higher, columns are hollow; Telford is beginning to use minimum materials -Llangollen slender pillars compared to Barton -See people on top to give it scale -Pillars are hollow (efficiency) SLIDE 21 Image: Proadventure.co.uk/flickr 30

33 SLIDE 22 Image: Elizabeth N. Billington-Fox The people in this picture give you a sense of scale of just how tall these piers are, which are actually hollow to save materials and money in the construction. 31

34 SLIDE 23 Image: Elizabeth N. Billington-Fox -Closer look at structure exceptionally slender arches -Different aesthetic from the stone arches of past. -Minimum material iron -Been maintained important tourist place -In front = weather plate (actual structure are the verticals and arches) -Completed in

35 SLIDE 24 Image: Bicentenary Exhibition, pg huge competition for a (not The) London Bridge across the Thames 600 span. -Does not get built -This is Telford s design 600 ft single span to allow shipping to pass beneath -Way beyond what had been done before in any material (nothing has been done of this span before not even close) telfords design impressed the committee the most so the competition committee consulted many iron users, including university professors, to see if such a design was feasible. Although the consensus was that the design could be built, Parliament never acted upon it. -Interesting design and competition -The civil engineering critic of bridges = James Watt (another Scot) -Wrote a critique of bridge and Telford took it seriously in his design of his next bridge. 33

36 -The measures of structural art -Telford defines it in 1812 in Edinburgh Encyclopedia -Symbolic is controlled within the disciplines of scientific and social. -Telford considered efficiency, economy, and elegance in his work, yet as a structural artist matures and sees the work built, they critique their own work. It was Watts critique of London Bridge that led him to think this way -Our first CCA: Iron Bridge vs. Craigellachie -Give an analysis of these two by showing, as Telford did, that Iron Bridge is not a great work of structural art 34

37 -Comparative Critical Analysis -Want to see what is happening in Britain as they are rapidly building their infrastructure -[go over slide text] -Telford s own he is first person to identify structural art -Three terms: scientific, social, symbolic 35

38 -Our first CCA: Iron Bridge vs. Craigellachie -Give an analysis of these two by showing, as Telford did, that Iron Bridge is not a great work of structural art -He compared Craigellachie to Iron Bridge -Regarding materials point of view (efficiency): -Iron Bridge = 100 ft span -Craigellachie = 150 ft span, but 1/3 less material for longer spantherefore more efficient -From the efficiency standpoint, the Craigellachie is more efficient; but keep in mind the Iron Bridge was initially made as an advertisement -Regarding Cost (economy): Cost of these bridges is hard to find but can get a sense of cost: -Craigellachie arch built in pieces (subassembly - 7 pieces, 4 lines of them, 28 identical pieces). Telford is using mass production to get economy. All cast in one mold in Wales and shipped by sea to Craigellachie (northern Scotland). Therefore much more quickly done. Although don t have exact cost comparison but can determine some things by examining as we have. With fewer unique parts and mass production involved, we can reasonably assume that the iron bridge was less costly to construct. -Regarding Symbolic next slide 36

39 -Iron Bridge is the wrong shape -Craigellachie it is circular but so flat that can t see the difference between it and a pararbolic shape. Telford made it a flat circle (not parabola) so each assembly is the same, cost effective. -Iron Bridge is mutilated (Telford s word) the arches bang into deck discontinuous ambiguity -Little circles, decorative features, no place in a bridge. -Whereas the Craigellachie is continuous between the abutments (no mutilation) -Craigellachie economical and efficient but also aesthetic; uninterrupted arch (more attractive to me) -Metal bridge complete unity -Two arches laced together to form trussed arch, made in a form that appeals to him. -Connection between arch and deck also aesthetic. Could have done in many ways without affecting the cost. -Aesthetic is based on what is needed for the structure rather than something 37

40 that is just added on (with no functional purpose). -We could criticize Telford why are there great stone towers in Craigellachie? 37

41 SLIDE 39 Image: Elizabeth N. Billington-Fox Looking at the spandrels, they were circular which were mostly for decoration -Looks like carpentry more than iron construction (and why not they were copying what they knew) -It takes quite awhile (30 years) before modern forms -See clutter in Iron Bridge 38

42 In the Craigellachie, the spandrels are these diagonals. A different vision, a different aesthetic. -Scale factor substantial size bridge rehabilitated and maintained -It doesn t destroy the idea that the Iron Br is a great work because it was so innovative, using this material for the first time. It is an important structural work. -Choice of the forms is an aesthetic choice because there are many ways of doing it. 39

43 -1820 Telford is elected president of the 1 st formal engineering society of modern world: institution of civil engineers in London. -Great Britain = best engineering country in modern world -Identified as single most important engineer leading engineer of the modern world; he s world famous -Had fine personality, maybe part of why elected president -Even if we forget about aesthetics,telford is the most accomplished structural engineer of this time and yet considered himself an artist (see this trend in others that we will study) -Telford was the first designer who gave weight to aesthetics. First modern engineer to show that a concern for aesthetic does not compromise the technical quality but can improve it. -The people we are going to talk about are not a separate group of artsy people just building elegant structures, they are the most accomplished and sound engineers, technically competent and artists. That is one of the themes that runs through this course. 40

44 Here s a video explaining what is civil engineering. 41

45 SLIDE 34 Image (top): Elizabeth N. Billington-Fox Image (bottom): ASCE ( slide 17) -Now we will find that these structural artists move slowly towards their structural art -Telford s criticizes himself and James Watt -We are going to compare Craigellache to the Mythe and see the mistake that Telford made with Craigellache. Proud Scots giving their thumbs up when both ICE members and ASCE members gathered in the Scottish town of Speyside to officially designate the Craigellachie Bridge a civil engineering landmark This was in 2007, which marked the 250 th anniversary of Telford s birth 42

46 SLIDE 36 Image: Flickr by Stuart Gordon 43

47 SLIDE 37 Image: Wikimedia by Philip Halling We re going to compare the Craigellachie and compare it to another of Telford s work known as the Mythe bridge. It s very similar in span and general form. 44

48 Image (top): Elizabeth N. Billington-Fox Image (bottom) Elizabeth N. Billington-Fox The spandrels were the difference. -[Top= Craigellachie, Bottom = Mythe] -Artists became their own severest critics -Telford notices that the spandrel configuration of the Craigellachie was not the most efficient -Fixes it with Mythe bridge -Craigellachie -designs so that the bisector of the diagonals are perpendicular to arch. -Realizes that diagonal loads are not shared, will mostly go down vertical piece (gravity travels straight down) -Mythe -diagonals are placed so load is distributed more evenly in diagonal. -Bisector is vertical -In this sense the Mythe bridge is superior to the Craigellachie Bridge 45

49 -Both great works however 45

50 SLIDE 39 Image: Wikimedia by Philip Halling -Mythe -As overall bridge, not as impressive (as Craigellachie) because of the break in form at the abutment and the visual difference on either side of that break. -There is also a break in Craigellache Craigellachie is not as big of a bridge 46

51 SLIDE 40 Image: -End of steel stonework -We can critique in two different forms: -One designer against another -One designer two designs 47

52 SLIDE 41 Image: Bicentenary exhibition, pg. 23 And here is one of Telford s longest span works. -Menai biggest bridge and last bridge of his career competed in ft span -1 st carefully engineered suspension bridge -There were earlier ones but most of them failed in wind (see why later on) -A major event in Wales (western wales, road to Ireland) 48

53 Why was this bridge built? Act of Union 1800: merged Kindom of Ireland with the United Kingdom of Great Britain Connect London to Dublin (needed quick way to get to ferry at Holyhead on the tip of the island of Anglesey) 49

54 Critique Side spans have arches and suspension (two modes of support from above and below) Telford did it because was afraid of wind. Wanted to make sure back spans heavily anchored Still has ambiguity deck can be carried by arch or cable (both not needed) Worried about wind that s why he used both -Just before it opened, Telford s resident engineer noticed undulations from gusting winds. -Telford added bracing which cut down movement -10 years later (2 years after Telford s death) bridgekeeper reported large oscillations. -Unfortunately no action was taken and in 1839 a gale tore part of the roadway loose. -Telford s writings in 1820 s and his resident engineer s field observations show how horizontal wind can cause extensive vertical motion in a suspension bridge. SLIDE 43 Image: Flickr by JustinPoulsen 50

55 SLIDE 45 Image: Rickman, Plate 71 -Trying to get it to look as light as possible -Although towers look heavy, they are hollow, like Llangollen 51

56 SLIDE 46 Image: Flickr by bvi

57 Image: Flickr by bvi4092 An important definition: span. When I m referring to the bridge span, I m talking about the longest unsupported length, not the full length from one end to the other. 53

58 Image: Flickr by bvi4092 Here is the definition of the cable, which is in tension. The tension is imposed because the suspenders (the vertical elements) are pulling down on the cable causing it to be in tension. The form of that cable is parabolic. 54

59 SLIDE 47 Image: David P. Billington Telford designed his bridges before the Railroad age which is where we move to next: Brunel and Stephenson. -Illustration of dense population in GB and need for RR which begins in GB in Manai not a RR bridge. RR introduces new dynamic heavy loads 55

60 -Isambard Kingdom Brunel ( ) went to work with his (engineering) father on the boring of a tunnel under the Thames seriously injured (part of the tunnel gave way) family sent him to Clifton for recuperation - That year there happened to be a bridge competition in Clifton - Brunel, with no previous bridge design experience, proceeded to make 4 different suspension bridge designs, each with a central span far greater than any previous bridge elsewhere (from 890 to 916 feet) so we were just talking about 500 ft for Telford (an experienced designer), so we can see that Brunel was quite courageous in his designs -The bridge commission therefore felt uncertain about judging the 22 entries so they asked Telford (then 72) to be the judge. 56

61 SLIDE 49 Image: Body, Geoffrey. The Clifton Suspension Bridge Here s an entry, an underbelly truss-type structure. Notice that the supports are no in the water. -Competition that tells us the state of the art at the time -Here are some entries (none are Brunel s): -One design, underbelly type truss 57

62 SLIDE 50 Image: Body, Geoffrey. The Clifton Suspension Bridge One that is classical and unbuildable 58

63 SLIDE 51 Image: Body, Geoffrey. The Clifton Suspension Bridge Arch or able? Both?! Here is an ambiguous form. The engineer was likely to be concerned about the wind effects for long-span bridges. -Worried about wind and therefore arch stabilizes the cable 59

64 SLIDE 52 Image: Body, Geoffrey. The Clifton Suspension Bridge Telford (best designer at time) who thought all designs were bad so he made his own (slide 52 image) -This is his design -He moves the support inwards instead of keeping them out of the water to shorten the span and ensure that it will stand in the wind. -Brunel thinks it should be able to span the distance. -Kind of ridiculous in a way, putting huge Gothic-like towers. 60

65 SLIDE 53 Image: Elizabeth N. Billington-Fox -Does not want to build longer span than Menai (because Menai is having trouble with wind). Idea of going from cliff edge to cliff edge (what is usually done) would make span too long. Brunel objects to Telford s design in a letter to the commission (says that those two huge towers are not necessary should be able to span cliff to cliff) All competition entries were scrapped, new competition later on. 61

66 -Commission holds another competition in Brunel decides to enter competition with this design -Clifton Bridge, still standing today SLIDE 54 Image: Flickr by Ben Salter 62

67 -Work began in 1831 but was suspended when political riots in Bristol made it impossible to raise funds revolutions in western Europe British had to stop a lot of building process -By 1843 both towers had been built but the bridge was not complete until 1864, 5 years after Brunel s death. -Three independent wrought iron chains on each side -With bridge construction at a halt Brunel turns to RR and between 1833 and 1841 directed the design, construction, and operation of the longest rail line in the world: Great Western Railway between London and Bristol -This line contained the world s longest spanning brick arched bridge at Maidenhead designed the Saltash Bridge near Plymouth for the extension of that Rail line beyond Bristol. (come back to this bridge later) SLIDE 54a Image: Boerkevitz from nl [GFDL ( or CC-BY- SA-3.0 ( from Wikimedia Commons 63

68 SLIDE 56A Image: Public Domain ( _Route_of_Great_Western_Railway,_1850.jpg) 64

69 SLIDE 56B Image: Elizabeth N. Billington-Fox Maidenhead brick arch bridge -Stimulated one of the most important paintings by Joseph Turner 65

70 SLIDE 56 Image: SLIDE 57 Image: -Turner is painting Rain, Steam and Speed painting of RR over Maidenhead bridge -Expresses industrial revolution -In front of locomotion = rabbit running (can t really see it) -Idea is that rabbit will be taken over the locomotive (natural things will be taken over by artificial things ). Can make anything you want out of it, Turner did not write about it. 66

71 -End of this rail line, London = Paddington Station, designed by Brunel in Iron arches SLIDE 58 Image: By IDS.photos from Tiverton, UK (Paddington Station, London Uploaded by russavia) [CC BY-SA 2.0 ( via Wikimedia Commons 67

72 All out of iron arches 1850 s, impressive at the time SLIDE 59 Image: By IDS.photos from Tiverton, UK (Paddington Station, London Uploaded by russavia) [CC BY-SA 2.0 ( via Wikimedia Commons 68

73 SLIDE 60 Image: Flickr by Pete Welsh, Called a lenticular truss (in the same of a lens) 69

74 SLIDE 61 Image: By Geof Sheppard (Own work) [CC BY-SA 3.0 ( or GFDL ( via Wikimedia Commons 70

75 SLIDE 62 Image: Elizabeth N. Billington-Fox SLIDE 63 Image: Elizabeth N. Billington-Fox -Called a lenticular truss -Arch pushing out, cable pushing in -Top is in compression, bottom is in tension; horizontal components cancel out -Result = pure vertical load clever but ambiguous design 71

76 SLIDE 64 Image: William Morgan -Construction of Saltash, his greatest rival, Robert Stephenson, was by his side assisting him (rivals but friends) 72

77 -Rob Stephenson Brunel s rival (3 years older and died same year) -Begin to see case where rivals design same thing -Stephenson also designed many things -Had big company making locomotives as well -From north of Britain -His father = innovator of RR locomotive (George Stephenson) -On 5 pound note on one side is Queen Eliz, on other side is George with his early locomotive -French putting tower on $$, English their locomotive SLIDE 66 Image: "Robertstephenson" by Maull & Polyblank - Licensed under Public Domain via Wikimedia Commons - ephenson.jpg 73

78 SLIDE 67 Image: Rees (Early Railway Prints) pg Designed Britannia Bridge (RR bridge) over straights of Menai -Railroad age: different loads (breaking forces) -Constructed tubes through which trains went -constructed on shore, floated out and lifted into place. -Brunel on site helping Stephenson. -They were rivals but also friends 74

79 SLIDE 68 Image: Rees (Early Railway Prints) pg Strange bridge was supposed to be a suspension bridge but was too flexible for railroads made deck so stiff that realized he didn t need the suspension chains -So towers were built to contain cables but in the end were unnecessary -Economy was less crucial than safety at a time when bridge failures were common and in a society grown wealthy -No longer there was burned down. 75

80 SLIDE 69 Image: Image from Wikipedia, public domain -During the evening of 23 May 1970 the bridge was greatly damaged when boys playing on the bridge dropped a burning torch, starting a fire -As a consequence the bridge was completely rebuilt and reopened in 1972 with the spans supported by archways. The deck has two levels: the lower still carries the rail line, and the upper supports a single-carriageway section -Section of the original wrought-iron tubular bridge standing in front of the modern bridge 76

81 -Britannia vs. Saltash - lenticular looks like lens -460 vs Recall Britannia was originally designed as a suspension bridge which explains its greater cost and weight -Cost have good documentation -Difference in cost is because of the form 77

82 SLIDE 70 Image: -Menai Straits with Stephenson Bridge in same image -Telford did not design RR load 78

83 -Stephenson and Brunel were both artists in iron structure but they were caught up in the frenzy of RR to such an extent that neither would stop long enough to reflect deeply on structural form as did Telford. -Telford Stephenson and Brunel had no immediate successor so to speak in Britain; however outside of Britain other structural artists developed as we will see -Britain is ahead of Industrial revolution and in engineering, but behind in formalized education. Lack of tradition 79