 All right. Good evening. Thank you for coming. Welcome. Let's get started. We have a wonderful lecture tonight by a good friend of mine, Tom Leslie, who is the Moral Professor and Architecture at Iowa State University. I think he and I almost overlapped at the University of Illinois where he studied and then had gone on to Columbia. Prior to teaching, he worked with Norman Foster and partners in London and worked on some exciting projects in Omaha, Nebraska and Rydia and Stanford University Clinical Sciences Research Project. He's the author of several notable books that I've showed some of my students in class this week. One on Louis Kahn, Building Art, Building Science, Chicago Skyscrapers, and the one I think we're going to hear about tonight, the most recent, Beauty's Rigor, Patterns of Production in the Work of Pierre-Louis Générvy. His research in historical relationship between engineering design and construction has been funded by several notable organizations, National Endowment for Humanities, The Graham Foundation, American Philosophical Society. His research has been published widely, including in the Journal of Architectural Education, Journal of the Society of Architectural Historians, Construction History, Design Issues, Technology and Culture. And I think Tom is here this week as well. I tapped him on his visit while he was in Providence for the Society of Architectural Historians Conference. He has appeared as an expert in several realms in the BBC World Service, Australia Broadcasting Corporation, New York Times, etc. Also, I share with my students this morning, Architecture Farm. And that's his blog on WordPress, which is an active online research notebook and there's a posting, I think, just last week having to do with the tragic collapse and fire at Notre Dame Cathedral. So if you want to know a little bit more about that and the history of that roof, you can check out the Architecture Farm. He has quite a teaching resume as well, one of his passions. He's helped visiting positions at the University of Technology, Sydney and Australia, the Bauhaus University in Weimar, Germany, University of Bologna, and the McCormick School of Engineering at Northwestern, where he's a full-adject professor. He's won several awards, including from the Association Collegiate Schools of Architecture, U.S. Green Building Council, and the AIA. And most recently, Tom, which is sharing with me one of the rights and privileges there too, has been awarded Fellowship in the American Institute of Architects. So please give a warm Bristol welcome to Tom Leslie. Thanks, Tom. Thanks for coming out tonight. So my, as Bob said, my research looks at the way that engineering and construction and design relate to it and influence one another. Yes. Oh, you really don't need to see the screen. And so that's been my teaching, but that also stems from where I practice. Foster's is one of these firms that believes that engineering and construction of us is architects that kind of grammar or language that we work with. And one of the examples that I've used continuously in teaching in one of the great heroes in Foster's office was this Italian designer and builder named Pierluigi Nervi. So Nervi had always been a kind of familiar name, and I knew about him as an engineer and knew that he was the designer of these incredible kind of lazy, almost spider web-like roofs in Italy and elsewhere that had achieved so much notoriety, especially in the 1960s. And I wanted to kind of see if I could figure out or help to understand why Nervi's roofs, why Nervi's designs seem to attract so much attention and so much critical love when other long spans of the era did not. And the example that I sort of use all the time is comparing Nervi's pallets at the Della Sport, a building that we'll come around to here in a little bit, with a reinforced concrete shell structure that's much bigger, should be much more impressive. The Kingdom in Seattle, which was so much loved that less than 20 years after it was built, it was torn down. Or 25 years after it was built, it was torn down. It was generally regarded as a supremely kind of ugly building. Great accomplishment, a much bigger building than Nervi's, so why do we respond so well to one and so kind of poorly to the other? And the sort of working hypothesis is that Nervi was more than kind of just an engineer or more than just a builder, but it was the relationship between these two kind of realms that make his buildings so special. So compelling when other shell structures of the era maybe aren't so much. So this project was to go back and to try to trace Nervi's career and to see what made him different basically from other designers, other engineers at the time. And in fact, you can go all the way back to his college days. Professors are very important in our development as designers. And Nervi attended the University of Bologna, which had one of the best civil engineering programs in Europe at the time when he went in the early or mid 1910s. And he had two professors in particular that he wrote about frequently. One of them, Silvio Canavazzi, on the left was a theoretician. What we might think of as a kind of white collar academic, didn't practice, but was one of the leading theorists of hyper-static structures. Concrete is still a relatively new structural material. It's very difficult to figure out the kind of statics of it because there's so many possible load paths. And Canavazzi was one of the ones who started the mathematical process of trying to calculate and concrete. The other one, Tilia Mugia, was exactly the opposite. He is what today we might call a professor of practice. He had his own contracting firm, and he taught not reinforced concrete theory, but reinforced concrete construction. So how you actually go out and kind of form the material into the shapes that Canavazzi is trying to understand from a mathematical point of view. And these end up being two opposite poles but very important influences in Nervi's life. He went on to not only become a capital E engineer, someone who designs and calculates structures, but he had a second firm that actually went out and built the buildings that he himself designed. Nervi's apprenticeship was with Mugia. He was one of these like straight A students who the professor hired right out of school. And he was super intended a lot of Mugia's work in and around Florence, and particularly in this one town called Prata. It has always been a center of Italy's textile industry. These projects are super straightforward, kind of boring reinforced concrete factory buildings built in an era when concrete was kind of ascendant in industry because it was both fireproof and kind of easy to build. But they occurred at what you may notice was a particularly interesting and particularly fraught time in Italian history. Mussolini took over in 1922 and by 1934 when, by this point Nervi had taken on ownership of his own firm and had started building buildings on his own. Fascism had taken over Italy completely. Mussolini had invaded Ethiopia and the rest of the world had basically cut Italy off from World Trade. Mussolini had this idea that that was going to be fine. Italy doesn't need the rest of the world. We can supply all of our own building material, all of our own food. And Nervi had this kind of falling out in a way. Early on he actually was elected president of the Fascist Syndicate of Engineers in Florence, but within a year he resigned because he felt that the strictures being imposed on engineers and builders were kind of unhealthy. A fairly brave thing to do. And the sort of other piece of this is that in fact Italy did not have a whole lot of building material on its own. It's kind of fortunate to have a huge variety of stone. But these two maps tell a very different story about how you might build in the 20th century. On the left is a map of all of the iron ore deposits in Europe in 1913 and on the right the other thing that you need to produce steel is a lot of fuel, a lot of coal at the time. And as you can see, Italy is burdened neither with extensive iron ore deposits nor with extensive coal deposits. It has one little mine on the island of Elba and basically no coal. The other thing that is sort of interesting about Italy's natural resources is they have no old growth timber because since the Roman era people on the Italian peninsula had been harvesting and farming timber not only for their buildings but also for fuel. They have no coal therefore they have to burn their trees to eat their houses for most of the last two millennia. So in fact this kind of brave idea that Italy can go it alone is completely wrong-headed. And Italy can't build with steel because it has to import every bit of steel that comes into the country. It's impossible but if all the embargoes that come into play in the 1930s it becomes very difficult and you can imagine very quickly why you would build in concrete instead of in steel. Nervi sort of bravely by 1938 is publicly against this idea of what's called autarky or building using only what you have to hand within your country. Mussolini and the fascists all of the contractors, all of the architects in Italy to go back to this Roman way of building with brick and building with travertine. And Nervi writes an editorial, a national paper in 1938 where he basically says that this seems to be a very kind of native way to build and it certainly looks like it, right? Mussolini's maybe more interested in sort of recalling the grandeur of the Roman Empire than a really serious attempt at efficient building. But Nervi says that this essentially ignores what the engineer can do and he says that if you take just a little bit of steel that we can get in Italy and use it wisely to reinforce concrete construction you can actually build for less money than if you rely on just native materials alone. The buildings are lighter, they don't require so much labor, they don't require so much fuel like bricks and things like this. So Nervi has this idea of taking the very limited resources that he has available and trying to kind of make the most of them. And very soon he moves from Florence to Rome. He builds this apartment block along the Tiber just north of Piazza del Popolo. He moves his engineering office into the first floor and he moves his family into the top floor and this is where Nervi lives and practices for the rest of his life. That is the kind of white collar professional office that he has, the kind of legacy of kind of at-seat. At the same time though, Nervi and first his cousin and then a business partner at Bartoli open up a contracting firm and they buy some land south of Rome in the Maliana district and they open up a contractor's yard where they can both kind of store material and also where they can experiment. This is one of their experiments that still exists in 1946. This is a prefabricated warehouse out of a material that I'll talk about in a second called Ferris Cement. And so I sort of imagine Nervi like in the morning going in like necktie, white collar, doing the calculations, writing all the correspondence and then in the afternoon kind of rolling up his sleeves going out into the job site yard and with his workforce getting his hands dirty and experimenting with ways to form and to make concrete. Again, these two kind of opposite poles, right? Thinking about the design and thinking about the construction. He and Bartoli are wildly successful. They get a commission in two stages for the football grounds in Florence which is still used by Fiorentina. In 1930, with Nerviosi as cousin who's a little more conservative, they build the main grandstand with this cantilevered roof that attracts a lot of attention for its sort of daring, swooping form. And then with Bartoli, his new business partner in 1932, they build the other grandstand where Nerviosi solves an architectural problem which is how you bring people in from the back of the grandstand so they can fill up from field level up with these giant kind of helical staircases. It's difficult to calculate. Very tough to build but you can almost imagine Nerviosi realizing that he now has the tools with which he can experiment. He can calculate stuff in his office. He can go try out the form work and see what other things work in the job site yard or the job yard. And so when he goes on site to build something this maybe is the third or fourth time that he's tried technique of forming. So he can build more daring structures and then most contractors will be asked to build. He can design them more daring than most engineers would be comfortable with. So as Italy slides toward World War II, the steel crisis gets worse and worse. And finally the Air Force in kind of desperation for new hangers for its planes sends out a call for a competition where they will design hangers in concrete instead of in steel. And Nervi responds with a proposal for a very efficient structural form. This is the hangar that ends up building and as you can see it's what's called a lamella structure but done in concrete instead of timber or steel which is what we normally see these in. It's a vaulted roof so it relies in part on kind of arch action in one direction and it's the lamella forms do two things. One is they basically take a very thin shell concrete roof and stiffen it but you can think about it another way they basically trick the concrete into thinking that it's much thicker than it really is. So it's a little bit like a coffered ceiling like the pantheon removing a lot of the dead weight from what would otherwise be a very heavy, very thick roof structure. This is propped up on a set of 36 buttresses around the back, three buttresses across the front and you can see that there's a giant truss, triangular truss that goes across the opening and this is both taking the gravity load of the roof but it's also taking the thrust, the tendency of the shell to spread out and restraining and to beam in two directions. Very, very clever piece of structural engineering. It gets published not only in Italy but also worldwide. Nervy is sort of hailed as this kind of genius who's figured out how to create an aircraft hanger which usually by this point people are used to seeing in a lightweight material like steel or lumber in this very heavy and importantly very kind of native material reinforced concrete. Nervy is not quite so happy with it though. Even though it gets praised for its kind of structural daring he later points out that in fact this building had a lot of problems and in particular he said he was frustrated by the fact that in reinforced concrete you have to build the building twice. You have to build it first with formwork and scaffolding so you're using a lot of timber, scarce timber in Italy. And he said then the roof in concrete still even with all the coffering even with the lamellar structure was so heavy that when all of these ribs came down onto those buttresses as you can see in the construction detail on the right he said basically we were building a steel building anyway because the reinforcing was so intense right there so much reinforcing in it. And he's very quiet about this he doesn't say until well after World War II but he thinks that between his kind of engineering and his contracting skills like it must be possible to do this better. He goes back to his job site yard and he begins to play around with ways of making similar hanger forms out of precast units and this lets him do a couple of things. One if you're casting on the ground instead of up in the air you can use the same form over and over again. You can make these units in one timber form on the ground as they cure you can pick them up and put them into place and then reuse the formwork on the ground. You can also make much more complicated shapes this way so you can see here in an experimental span that he's building in Maliana that he's looking at ways of basically building what I think of as a veering deal arch a truss arch that uses moment connections and it takes all of the dead weight around what would be that arch's neutral axis. So saving as you can see like 60, 70% of the weight of that arch and at the same time finding ways to make it faster to cast on the ground he realizes too that you can sort of telescope the construction time. So while you're pouring all the foundations and getting all the substructure done another crew can be casting all of these members and you can have all of the kind of pieces ready to go by the time that the foundations are ready so you cut the time of the construction in half. The problem with this of course is that all of these precast units have to still connect to one another and to take advantage of concrete they have to perform as a monolithic shell. There is a sketch in there of the archives that you can see on the upper left where I think he kind of figures out how to do this. What you're looking at there is four precast units each with a little hoop of wire or rebar and that octagonal shape is basically a concrete plug and once all of those precast units are in place they just form that little octagonal box pour some concrete into that and as that cures it latches on to all the various rebar and gives a monolithic connection to the joints you can multiply this by a few hundred throughout the roof of a hanger and you have a roof that is kind of sufficiently monolithic or hyper-static. Here again in Maliana he's playing around with how you actually build this you can see again very many old truss pieces and if you look closely you can see just little bits of rebar sticking out into those joints so he's taking the minimal possible amount of steel deploying it only where he actually needs it and using his reinforced concrete plugs to make sure that those joints are monolithic that they will connect pieces together. As he's doing this he realizes that he's saving weight which saves money, saves on foundations saves on rebar at the connections he's saving time because these can be precast while the foundations are being built and he realizes that he's also saving money in terms of the equipment that he's going to need to rent because if you make all of these pieces small enough that you just need a small crane to place them into place instead of a big crane then Nervy doesn't have to go out and spend the money on one of these giant boom cranes build with smaller pieces of equipment. His firm is a fairly small like family-run firm they don't own their own cranes and this is something I think that we rarely think about that the size of the pieces that you're trying to lift has a direct bearing on the cost of the construction because you've got to rent the equipment to actually lift those pieces. So here later in Lectures to Architects he's talking about this project a freeway viaduct in Italy and he says that because of the fatal reliance on economy that's what actually determined the spans of this viaduct and likewise when he's building these hangers the second round of hangers he's found ways to not only reduce the size of the crane but as you can see from this shot to actually get rid of the crane entirely. This is a traveling scaffold that kind of is driven along the length of the hanger it has wrenches and pulleys that allow people to lift or work on to lift those truss pieces up into place. You can see that it's changed from a very ideal system to a more traditional triangular truss that is him on the left with the tie hand and pocket looking very pleased as well he should. What's kind of fascinating about there are a bunch of things that are fascinating about this round of hangers that he did in the midst of World War II one is that he's reduced the number of buttresses from 36 down to 6 you can see that he's taken out virtually all the weight of the roof and the arches. This system is monolithic enough that he came back and instead of a port-in-place shell he just put kind of asbestos shingles over the top to keep the crane out so much less weight he's saved on scaffolding because this thing here can just travel along the length of the hangers saved on foundations, saved on time and at the end of the project he does something very interesting instead of just having his work take kind of job site pictures like we're sort of all used to he sees this hangar being completed this is the first one that was finished on the coast of Italy and toward the Lago and he calls Studio Vasari which is Rome's best known architectural photographer and he says come out and before the roof gets put on this one I want you to take some architectural photographs of it This is interesting because these are really pure engineering structures in fact in the archives there are a handful of drawings that show what the building is going to look like what the hangar is going to look like but there are literally hundreds of drawings where Nervi is doing the graphic statics on the left to figure out how the hangar is going to work as a piece of structure hundreds of drawings that are basically shop drawings showing what each truss piece is going to have to look like what its dimensions will have to be to go into place and dozens and dozens of drawings of the scaffolding that Nervi used to actually erect the pieces there are almost no drawings that we would think of as architectural he didn't really think about what it was going to look like until he saw this process and its completion at the end and realized that almost accidentally he had come around to making architecture not just building, not just engineering but something that solved the problem and was truly beautiful at the end so there is one set of lessons there a really refined process born out of really really difficult conditions leading almost accidentally to something that is truly beautiful truly kind of compelling aesthetically during World War II he gets a second commission from the Italian military that is even more pressing in addition to not having steel for hangers the military doesn't have any steel to build ships and they also don't have any timber to build ships and the Navy goes to the country's engineers and says we are kind of open to suggestions and Nervi responds by saying he thinks he can build boats and ships out of concrete and the Navy gives him a commission for four demonstration hulls these are two of them that you see here they give him a shipyard that has no power and no equipment and basically say good luck and what Nervi does is borrow a kind of old French technique that an Italian is called Ferro cemento which you can see the detail here on the left I'll show this in a bit more detail here in a second it's a way of making a very very thin sheet of concrete that's reinforced with very very light steel mesh you can see there are a couple of rebars there those are basically the kind of the lofting lines I can use terminology like that in Bristol where you all know about ship design in the Midwest you say like lofting lines people are going to be talking about here maybe it's a little different so you can see that he's got to make complex curves so he uses what little rebar he can get not necessarily for reinforcing but as kind of the way to get this three-dimensional hull shape into space once he's done that all the dash lines are these layers of thin metal mesh expensive but possible to get immediately and then into the metal mesh he gets labors mostly unskilled to just trowel a lightweight aggregate free cement into the kind of voids between all of these screens and when all of that cures what little steel there is is distributed throughout the concrete so completely that ferro cement works sort of partially like concrete but also a little bit like steel it's tough it's ductile, it can take bending it's sort of perfect for shipbuilding these four hulls get built by 1942 Italy is essentially abandoned it's Navy it's kind of decaying but they do get tested and they survive all the kind of torture tests that the Navy does to them later in life Nervi comes back and builds his own sailboat for his family out of ferro cement so there's kind of proof of concept what Nervi realizes though is that if you take this kind of shipbuilding technique and turn it into a fabricational technique for architecture you can take these prefabrication ideas that he has and sort of super charge them so ferro cement he realizes you can go from a three inch thick prefabricated piece to a piece that's more like one and a half inches so you save 50% of the weight of concrete which means you save on all the structure that holds that up you can see here this is one of the stadia that Nervi did for the Olympics and he's using very lightweight cranes to pick up roof elements made out of ferro cement that will be placed into yet another cantilever roof over the stadium this is the fluminio today it's kind of a ruin but I've been lucky to be part of a group some of whom you see here who've convinced the city of Rome to restore this building and particularly to restore this very innovative roof it's basically built out of dozens of little ship hulls and it has this kind of library of techniques he's found a way to prefabricate concrete to connect a prefabricated concrete in a way that gets him the benefits of reinforced concrete he's found a way to supercharge even that into this kind of magic material that works sort of like concrete sort of like steel and all of this has come about through processes that don't require a lot of equipment and that are kind of algorithmic in a way that we don't often think of we think of algorithmic design as being super complex Nervi doesn't have grasshopper or anything like that what he has are basically unskilled laborers and not a lot of power or lifting equipment and so he's had to find a way to make all of this stuff basically with hand labor and to take all of the kind of craftsmanship out of the process and find ways to use very very simple repetitive techniques to get very complex forms built after the war in 1947 Nervi is approached by the city of Turin which is in the north sort of Italy's kind of industrial center it's like the Detroit of Italy it's where fiat's have always traditionally been made Turin has decided that as a way of kind of celebrating back into the society of nations they are going to host the international auto show in 1948 and everyone is very excited about this the only problem is that the exposition center like the rest of Turin was absolutely leveled by bombing during World War II the organizers have eight months and they put out a call basically for proposals and they are the only firm that says we think we can build a full scale exposition hall in just eight months and Salone V which is the big sort of corrugated hall is the one that they built in 1947-48 the other one Salone C is off to the back there they built that after the automobile exposition and what Nervi does basically is to take the ferro cement technique that you perfect it in the shipyard for the first time to the long span roof these are drawings that my student research team did about halfway through they started calling these the Ikea drawings for Turin and that is just about right there is a process here where Nervi breaks the construction down into small discreet events that he can give to individual teams of unskilled laborers and say do this one thing do it 108 times when you are done like just stack the finished products up in the job site yard while we are over here pouring the foundations they built out of brick and clay these molds over which they take metal mesh easy to get now that World War II is over they bend those over the molds they have laborers trowel that lightweight cement into those metal mesh screens they take those off of the molds wait for them to cure literally just stack up these families of precast units over and over and over on the left this is a Saloni C not Saloni B but you get the idea very very crude techniques very simple they just require some simple instructions and then repeating those over and over again on the right that is the contractors yard next to the Saloni B where you can see that as they are pouring the foundations they have literally hundreds of these things lined up mass produced using manual labor Nervi has broken the roof down into these small components so that they can be moved around each one of them by three or four workmen and as you can see it doesn't need a crane this is two guys with a pulley winching one of those units in place they are going to turn it put it on this traveling scaffold slide it down a rail until it butts up against the member right beneath it they will grout those together once they get a complete arch they will pour a little concrete in channels in the top and bottom with some reinforcing and what they will end up with is a long span kind of two hinged arch roof that is corrugated so again like kind of tricking the concrete into thinking it is very deep while in fact it is very thin at the last minute Nervi realizes that if you take the material away from the neutral axis and put glass in its place you will get these very nice skylights which bring light in on a kind of regular module and at the end of each one of the hulls to stiffen them while they are being moved around he includes these V shaped diaphragm walls and at the end when the things are all in place and yes it opened in time for the 1948 exposition what you get is this kind of dialogue between this gigantic span and the kind of very human scale that gets imprinted on that span because of the process and once again like almost accidentally right Nervi has not stopped to think about what this is going to look like all these done is kind of paid attention to the process and how to get this job done in eight months and at the end you kind of stand back in the rigor and structural thinking coupled with the kind of human scale of the fabrication and construction have kind of almost accidentally again created like architecture right you can see at the back there is this little apps and this was a requirement that the city they wanted to have a place where like the prizes could be like an honorific sort of space at the back of the hull they insisted on making it a half dome which makes perfect sense architecturally and makes absolutely no sense structurally because a dome only works really if you can complete the circle and if you can put some tension members down at the base to keep it from bursting a half dome literally just wants to spread out right wants to push it but just inside just like an orange so Nervi is kind of confounded by this right it's bad enough that he has to build this thing in eight months now he has some architects idea of what a structure is going to be and he's got to build that too and he realizes that in addition to trying to buttress the dome around its perimeter with this kind of semicircular roof that you can see he has to save weight one of the keys to making the dome work is to make it as light as possible and what he does is he takes the ferris cement idea that is structure in the main hall and he realizes that you can use that light ferro cement that thin technique to basically make coffering formwork for the dome so here on the left you can see another crew that's making these triangular and diamond shaped pans kind of like hats right they've got a kind of void in the middle and then a thin brim around the edge those are stacked up next to each other the brims of the hats the bottom of these voids that will become concrete ribs and the kind of diamond shapes will basically be coffers in the dome that will take out most of the dead weight they'll come back and they'll pour a couple inches of concrete over the surface and what they'll end up with basically again is either a thick concrete shell with most of its weight removed or think about it another way a very very thin shell concrete roof with this network of stiffening ribs below it very sort of clever structural idea executed again on a scale where two or three workmen can lift each one of these units and you get not only the half dome that the clients wanted but this very intricate the first of these spider web kind of roofs that they're designed and again stepping back from it kind of rigorously conceived structural idea very human scale production process and kind of magically at the end this work of great kind of architectural beauty and this becomes I think one of the key techniques that Narvae uses over and over again this idea that you can make form work not out of timber which historically is difficult to do in Italy but then you can actually make form work out of concrete and in particular out of ferro cement almost right away he applies this to a tobacco warehouse in Bologna and what he does is he invents this kind of building machine this kind of form work machine that you see on the left he puts ferro cement forms in the top and you can see because they're ferro cement instead of timber he has a lot more freedom in what the shape of those forms can be and he kind of in a way signs the building with these slab details we're used to seeing waffle slabs where the joists are just straight and just connected 90 degrees well Narvae knows that as those joists approach the supporting girders they collect more and more shear and they don't necessarily have to get deeper but they have to have more cross sectional area and so you can see that the ferro cement forms flare out and provide space for the joists to get wider as they approach the beams a kind of signature of more and more shear in the connections and not so much bending which of course is maximum do you have to do this? No of course not you can just add more rebar but Narvae thinks it's important as an opportunity to express kind of what's going on there again not so many drawings of the warehouse itself but loads and loads of drawings of what Narvae wants the finished slab to look like and how these building machines are going to be built so that you can use one set of forms that here instead of leaving them in place he oils them they cast a bit of floor and after a couple days when the concrete come up to working strength they can drop these forms down and move them to the next bay so it's almost like they're just stamping one bay after another into the air we had a lot of fun with this we built not only the forms but then we came around and built the slabs that went on top of them and like no surprise you get the same pattern again and again and again the warehouse is about a mile long it's not sort of 80 or 90 feet wide and so Narvae is thinking of the job site as an assembling line and taking in this case they built 16 of these forms and they just kind of skipped after each other down one floor there's one crane at the end that would then pick them up and put them on top of the floor they had just made and they would come back so they just went back and forth like a typewriter for eight floors this building like many other of Narvae's buildings is kind of a ruin it's possible to sneak in though I didn't tell you that and it has this incredibly beautiful floor slab that if you're a kind of waffle slab connoisseur this is how to do it right and it's just this little detail that Narvae must have known almost nobody was ever going to see but the freedom that this form work system has for him allows him to kind of sign the building slightly more famously this is a wool warehouse on the outskirts of Rome where someone in his office said you know it's not just about tweaking the details you can actually kind of reshape the whole kind of waffle slab it is something that's much more structurally expressive and so here the form work is made so that the ribs actually trace the lines of isostatic force in the slab right and that's how the weight of the slabs is getting collected over these column forms it was pointed out even in Narvae's time that this is the pattern for a flat slab and once you put ribs in that slab the isostatic shapes change and Narvae's response was like come on this is like a beautiful waffle slab right and interestingly here he is interested in beauty but he's interested in beauty that comes from a structure not just performing a structure but also communicating a structure right telling you something about how the slab works or telling you something about how okay another slab works but in a way that may sense on this kind of kind of module so all of this comes together in some of these great domes that he builds and the turning point of his career is really the 1960 Olympics which are held in Rome and Narvae at the time is pushing 70 so he's got a long career behind him already and this really starts as kind of the second phase of his career it's a sort of astonishing thing for Italy to host the games like the Axis Powers after World War II all hosted the Olympics within 30 years Japan Italy and Germany Italy was the first and they proposed to do it in three ways they would use the ancient some of the ancient sites the marathon was run on the Via Appia a wrestling to place in the cylinder of Max Enches they very frankly used a lot of the fascist buildings that had been built in the 30s they thought instead of whitewashing in the past they wanted to be very clear about acknowledging the fact that that era had occurred and then they built these new buildings and really big really big events to show that Italy was kind of looking forward a nice bit of rhetoric the International Olympic Committee was skeptical that they could do this and so in 1957 they were asked to build a demonstration project an arena that would show that they were capable of building these big arenas Narvae was on the committee that wrote the specs and then he turned around and was the only firm that bid on those specs so Narvae is not only a great engineer but he was also an absolute shark of a businessman and the way he proposed to do this was to take that technique that he had used in the apps of the Turin Hall and to kind of blow it up in scale so on the left this is the job site yard this is going on while they're digging the foundations you can see that he's got all of these diamond shaped pans that have that kind of hat like section and you can also see that it only takes a couple of workmen to move a couple of those over to the job site on the right you can see them tiling the surface of the dome with these diamond pans these got left in place Narvae realized that this meant that you could get a reliable finish on the interior you weren't so worried you didn't have to be worried about what was going to happen when you peeled the formwork off and you can see that there is a crane so lift all the pieces into place they refined the process down to the point where they only needed to rent the crane for 60 days and they tiled the entire surface and took the crane down and got it off the job site in just two months so very very efficient you can see too that they're only a handful of construction workers on top of the dome so they were able to kind of refine not only the schedule but also the amount of labor that they took so they then came back they poured a thin shell dome over this formwork that's reinforcing in the bottom of what are going to become the ribs and the dome was held up or is held up on this ring of fork shaped port-in-place buttresses that go to a tension ring that's buried in the ground beneath it impressive enough from the outside a giant concrete dome that's really supported on these forks and absolutely breathtaking when you walk into it I've led probably eight or nine tours of this building and literally every time people are talking and sort of conversing with each other as they walk in and it goes dead silent because this is such an impressive space not because it's so huge but because it's a big enough span that's broken down into this very very human scale and every one of those diamonds is an element that three or four guys could pick up and it's up in the air it's surrounded by this glass curtain wall it got called a concrete pantheon it's only a few miles from the Roman pantheon so the comparison is kind of obvious and every got tired of this and finally pointed out to one journalist that it's easy to bring light in at the top of the dome and he had found a way to actually bring daylight from underneath the dome and so the whole thing feels like it's hovering it feels very very lightweight again though this is a system that is handmade there's only a crane on site for 60 days the sort of almost punchline to this is that everybody realizes that usually you start with the earthwork and then you build the roof on top of that and everybody realizes that actually what you want to do is build the foundations at the outside and then you want to build the roof and then you want to come in with your excavators and build and dig and build the actual bowl of the seating because then you're out of the rain you've built your own kind of weather guard over the job site on time on budget the International Olympic Committee has to admit that Italy can probably pull this off Nervi again writes specs for a bunch of the buildings gets a lot of them and finally gets told when it comes to the belladrome like enough you've done enough but he does four or five projects for the Olympics including the Palazzo Della Sport Palazzo Della Sport which is a span that's about half again as large as the Palazzo is one where interestingly he goes back to the Turin roof idea this is a corrugated ferro cement roof but instead of being extruded it's now on a rotational grid so they're all kind of these long skinny wedges of ferro cement but broken down into small pieces that can be moved around by hand and he throws kind of every technique he has at this you can see these kind of raking buttresses around the outside this was another important place technique that he developed for creating ruined surfaces out of tempered formwork it's a much bigger space it's not quite it's kind of architecturally appealing I think because there's so much going on but again it has this combination of incredible span and very very fine grained detail that sort of imprints the human scale onto this big span and it was really these buildings that elevated narrative from kind of cult hero to architects and engineers into international superstar the 1960 games were the first Olympics to be televised worldwide and so when Cassius Clay later Muhammad Ali won the gold medal in boxing the title ballot and the medal ceremony both were under the Palazzo's dome so millions of people worldwide see not only the athletic competitions but they see them underneath these incredibly finely scaled roofs and there we achieved this measure of celebrity that's very unusual for an engineer in the 1960s among other things the Palazzo shows up again and again and again as this kind of symbol of Italy's progress here in Vogue magazine in 1964 this should be a career goal for all of you your building should end up in Vogue someday you can see that it's elegant enough for a fashion shoot and Nerby's buildings show up again and again and again in Italian cinema you can see so here in Antonio the only film which takes place in the neighborhood around the Palazzo and all of these kind of long conversations you know Art House Italian film right full of these long kind of perambulating conversations they take place with the Palazzo in the background it's a symbol of kind of Italy's prowess not only in fashion but also in science and technology and this exposure for Nerby's career is a kind of consulting architect and he does these buildings in the last couple decades of his life where he pairs up with people in different countries none of these have quite the rigor or quite the power that the buildings that he does in Italy have and I think that's because he's kind of farming out the actual construction someone else is on site they're often borrowing the same techniques but they never seem to have quite the depth that the actual kind of Nerby built buildings have so here Australia Square in Sydney with Harry Seidler the correspondence between Seidler and Nerby is really funny because Seidler is just such a kind of fan and he'll send Nerby kind of sketches and ideas that he must know or find and Nerby writes back and says yes you know you're doing it right that's great and Seidler kind of goes off and built it with Pedro Baluski, St. Mary's Cathedral in San Francisco where this diamond or triangular shaped pan form is used to create these four high-par shells that they've leaned together and form a cross of the ceiling and then kind of locally up in Hanover Nerby actually does two sports buildings an indoor track and this ice arena, these are the buttresses on the exterior and the interior of Thompson Arena is fascinating to me because it's the sort of shape of the Turin Hall but it's the technique of the palates at the moment these are all ferrocement pans that are used to form and then to kind of finish fin shell concrete on the exterior so to finish among the invitations that Nerby gets in the wake of the Olympics he is invited by Harvard University to give the Charles Elliott Norton a series of lectures in poetry in 1961 and that is a pretty telling moment that a structural engineer and someone who is trained in the kind of really like hardcore mathematics and the kind of dirty hands job site of concrete construction and engineering gets recognized as a poet he gives a series of lectures that he later calls aesthetics and technology and building and he works very hard to try to distill his philosophy down into something that the kind of kids at Harvard can understand and this quote I keep coming back to because I think it contains so much of what he believed in so much of what I think makes his buildings stand out from his contemporaries aesthetics is very important to him he understands that we have this innate desire to do beautiful things to be in beautiful buildings and he says that that comes from two sources one of them is the objective data of the problem so static form for him is a universal language a cantilever in Hanover, New Hampshire wants to be the same shape as a cantilever in Milan, Italy no matter where you are the statics are kind of universal they may be empirical or scientific so those are scientific the empirical data of the problem might be we have no steel, we have no timber we're forced to work in concrete or we have plenty of steel so maybe the formula is a little bit different when he's working in America interestingly he says that these only suggest the solutions and forms we sometimes have this idea that the structure is somehow determinant that it tells you what your form has to be and Mary says no there's all kinds of ways that you can span a space we know that there might be certain solutions that we see again and again but these are just suggestions and the agency lies within the designer the aesthetic sensitivity of the designer understands the intrinsic beauty and validity that these suggestions might have that has to welcome them and then it's us like we model those suggestions we punctuate them, we emphasize them we have this kind of personal way of dealing with them that is the artistic element and it's not that art and science are opposed, it's that they're in this dialogue that I think you see particularly in his work interestingly there are a couple of kind of dualities in this that may not be evident at first technology and statics when Nervy talks about technology he's talking about construction when he talks about statics obviously he's talking about structure these two things do not always fit together easily and we've seen how Nervy tries to create ideal shapes but he has to achieve them in ways that take advantage of the few resources that he often has and I think more importantly that architecture engineering, like design in general there's always this dialogue between the kind of ideal world that's out there the kind of artsy world of mathematics and the kind of dirty hands world of Lucia and this much more refined world that all of our buildings kind of aspire to Nervy collected Renaissance art he read Dante for kind of fun he was definitely kind of aesthetically sensitive trained he was able to take that sensibility and apply it back to these quote-unquote objective data I'll just close by saying that in addition to my study on Nervy I was part of a team that reissued or republished these lectures by Nervy aesthetics and technology and building with a bunch of historians writing about what those essays kind of meant at the time and have been since so this is now newly available it was available previously only for a couple hundred bucks on eBay and now it's out in this new edition and I'll leave you with Nervy sitting at the table contemplating but surrounded even in his kind of elderly years with that picture on the upper left that Vasari picture of those early hangers conceived out of these incredibly rigorous conditions and yet almost kind of uncannily touching our ideals of architectural beauty. Thanks very much would you take a question or two? Absolutely. I was wondering if you could say a word about Nervy's influence on a relationship to contemporary experiments and construction and digital manufacturing and structural structures and parametrics and all that kind of stuff. His influence has been kind of diffuse there are certainly engineers who claim him as a kind of influence Kala Trava is the obvious one but Kala Trava is not a builder he doesn't build his own work and I think that a lot of his designs sort of lack the discipline to kind of distill Nervy's work into something else I think that the strongest influence is in the use of geometry and the use of kind of thinking about structure as not only the finished product but also the kind of algorithms that produce the shapes. How do we actually get these geometric ideas into the world I look at things like diagrit structures or the example that I use in the book is Foster's roof over the British Library which takes a kind of structural form and breaks it down into bits of glass and metal that you could actually make with a kind of simple patterning process. Even then, even when British Library was done, we didn't have the kind of information capacity that we do today. Today we don't think twice about panels that might be a thousand different shapes. We just send it off to the CNC machine and they kind of cut it. Nervy had the thing about how you create families of shapes that you use again and again and again. He's in a mass production kind of era. That doesn't translate perfectly today and we also don't build spans this big out of concrete so much every day. The economics change. I think it's more in that kind of bigger idea that geometry and pattern and the kind of algorithms of how we make stuff underlie all of these different approaches. There is a kind of the relationship between what we build, how it performs and how we actually get those forms out of the factory or out of the shop onto the site. I think that's probably where it's influenced. Any other questions? If I can throw one at you, Tom. So when does this fall in Billington's definition of structural art? I'm sure you've thought about it. Oh, I've thought about it. And it's not the first time I've been asked that. So Billington, for those who don't know is the kind of I would say he's like one of the founders of kind of structural history in a way. The pointer of this term structural art Billington is trained as an engineer. Taught engineering at Princeton for years and years and years. He's hugely influential. And in almost none of his writing do you ever see anything about construction or about fabrication. It's all about the shape and the form and how closely that relates to ideal. This, I think, is what you would expect from someone who has a fairly high-falutin engineering education and has never had to deal with a former contractor screaming at them on the job site. So I take very gentle issue with the kind of Billington stance that talks about structural art. I think that what that is is really architecture. I think that it is the kind of it comes from these three places the ideal forms which are absolutely out there but to actually get those ideal forms like us working slobs have to figure out how you're actually going to make them and how you're going to get all these pieces up there how you're going to create the ideal form. And so there's this dialogue that I think Billington doesn't always quite get. And to me that that makes it messier and more complicated but also much more interesting. And it means that as designers I think it gives us more latitude because as Nervey said it's not that the structural ideal is telling you what to do and I sometimes think this is what Billington kind of thought it's that it's saying there's a kind of range of options and some of them might be easier than others depending on whether you live in a country with lots of native steel or if the labor versus materials equation is different then maybe your form gets a little bit to me that opens it up in a way that allows room for us to come in and make this it's a big tie in all right well maybe perhaps Tom will take a question to him at the podium as you're filing out I believe we have a light coalition outside for those of us who are here so thanks again Tom