Jan Knippers (right) and Thorsten Helbig. t Photo Klemens Ortmeyer h r o R u t o g h o h e f

Jan Knippers of engineering firm Knippers Helbig talks about the importance of breaking out of model thinking.

Text Terri Peters

154 LOng Section STuctural Engineering 155 /germany Knippers helbig – not only structural engineers, but also that meets the design challenges. We mechanical and aerospace engineers – used this strategy for the Margaretengürtel Bao’an International are trained in model thinking. That’s why Bridge in , a project we did with Airport, Terminal 3 every book you find on engineering, even Knight Architects. It’s our first winning Massimiliano and my own, contains a table with a pool of bridge design. Our office is ten years ‘There are two basic things Doriana Fuksas On a cold Copenhagen morning, options for building structures that are old, and over the years we’ve entered Shenzhen / China I meet engineer Jan Knippers outside a subdivided according to the complexities many bridge competitions but were 2012 (under construction) closed café in the district of Vesterbro. It’s of geometry, basic load-bearing systems never successful. It could be because that architects should know Saturday, and the cafés in this part of town and so on. What engineers do is to look at all engineers are doing exactly the same Studio Fuksas designed don’t open until ten, but he’s agreed to fit these tables and choose options that meet thing: proposing very light, transparent about engineers’ an extension for the me into his schedule between a lecture the challenges of, and are appropriate structures. After ten years of failing to win Shenzhen airport, and at the architecture school and his flight to, the problem they want to solve. This bridge competitions, we reconsidered the Knippers Helbig took back to Stuttgart. This is a man whose time pool of options is influenced by history ‘light and transparent’ design goal. The responsibility for the façade. is in demand. He teaches at the Institute and experience, but it always follows bridge in Vienna is in a very prominent potential to be completely redefined. Shenzhen, and I took charge The building has a 200,000- for Building Structures and Structural a given model, which means that on a place at the heart of the city. It will be New design processes are causing such of the Expo project. But we m2 double-layered façade and Design (ITKE) in Stuttgart, gives lectures conceptual level the degree of innovation finished in late 2013. It is a pedestrian and a fundamental shift that new roles have have a team of about 30 people that work roof construction with spans in cities around Europe, and works on is not very high. The second thing is that cycle bridge with a free-form frame made not yet been established. Engineers now together on all projects; no one person up to 80 m. Knippers Helbig projects at Knippers Helbig, a firm with for an engineer, a good design means of laminated timber girders. The design have an opportunity to break out of model does it alone. The majority of us are developed a parametric design offices in Stuttgart and . He optimization of efficiency. Since my first achieves a positive CO2 balance and uses thinking, to go beyond optimization, to engineers, but we also have a physicist, tool for the façade, which assures me, however, that finding an hour day of university, I’ve been told that a good local materials. follow paths not yet taken. It allows us to a mathematician, two researchers and consists of 60,000 panels for a quick meeting is always a possibility. structure is one that uses the least amount go beyond the design of the detail and several architects. attached to a free-form shell We spot a place to sit and talk about the of material and is as light as possible. We Your lecture at the Digital Crafting focus, too, on designing the processes with windows of different impact of digital design on the engineering learn that these are the only criteria that Symposium yesterday was about the of design and manufacturing – and on What was your first big project? sizes. Besides providing profession, the best ways to create matter. And it’s not always true. potential of new processes of design designing a relevant tool. The Peek & Cloppenburg department store specific dimensional data structural failures, and new structural- and fabrication. How have these in Cologne [2005] was one of the very for each panel and each design research involving biomimicry. So a light structure is not always processes changed the way you You and Thorsten Helbig rare projects that included an engineering design iteration – and the best solution? practise engineering? established Knippers Helbig in 2001. competition. The architect, Renzo Piano, executing the definitive design A building project often pits No, not always. If you use timber for a This new digital chain of design and How did you begin working together? designed a five-storey building. The – the engineers came up with architects against engineers. Why bridge, for example, it might be good to fabrication is not only about new tools We both worked for engineer Jörg challenge for us was how to design a a geometrical solution for do you think this happens? use as much timber as you can, as long that allow for fancy geometries, but also Schlaich. After a few years there, we very light, transparent timber façade to the building’s 450,000 Jan Knippers: There are two basic things as it comes from renewable resources. about the whole conception of what decided to found our own office. We share be supported by the building’s concrete -member frame. that architects should know about Timber stores carbon dioxide, so it’s engineering is and what engineers can responsibilities. For example, Thorsten frame. We used vertically arranged trusses Photos and rendering Studio Fuksas engineers. The first is that all engineers possible to build a heavy timber bridge do. The relationships involved have the headed the Bao’an Airport project in with wooden members and horizontally

Erecting the main structure on site.

156 LOng Section STructural Engineering 157 Stuttgart/germany Knippers helbig The building has a steel skeleton and a concrete substructure. The skin that envelops the structure has a honeycomb motif on both the inside and the outside.

Mock-up. ‘It’s often better to work with lesser- known architects’

158 LOng Section STructural Engineering 159 Stuttgart/germany Knippers helbig running façade tubes attached to the lamella. The result is a €1 million research Those are some big names in pedestrian Bridge shell with diagonally spanned cables. The project based on what might appear to architecture. How do you choose which Knippers Helbig, façade has no support from the ground; be a simple little mechanism – just one architects to work with? in collaboration it’s attached to the structure at two ‘After ten years of failing to small component. But it’s really changed Engineers are often considered ‘good’ with Knight Architects points. We were faced with a large span our perspective on architecture. Looking because they work with famous architects. Vienna / Austria and a large deformation of the concrete at natural forms and understanding new We believe that sometimes it’s even better 2013 (expected completion) slabs, so the main issue was how to make win bridge competitions, we ways of creating function are what have to work with lesser-known architects the façade correspond to the light, emerged from this research. One of the and offi ces; we often have more options, In collaboration with delicate shell. Timber lamellas may look reconsidered our design goal’ major issues in biomimicry is scale. How more chances to explore ideas and to British fi rm Knight Architects, very simple, but from an engineering can material or performance be scaled for offer our own input. Take the Peek & Knippers Helbig won a perspective, it’s diffi cult to handle wood in application in building projects? Cloppenburg project, for instance, where design competition – open that way. Wood contains fi bres, which can the entire geometry of the project had to 37 teams composed of mean creep, shrinkage or expansion. We 3D surface. We needed many physical should look and how it could be made. Have you been to the site in Yeosu? been defi ned before we began. Even the engineers and architects – for worked a lot with mock-ups, considered models to understand the complexity It was a lucky coincidence that our fi rm No. Once we had fi nished the design stage design of the lamellas had been decided a footbridge in the area of various methods of attachment, and involved, and we had to keep certain was working at the time on precisely the and handed over our work to the Korean – not how to attach them, of course, the Margaretengürtel metro subjected the different systems to load- factors in mind at all times, such as the type of elastic deformation needed for contractors, we heard . . . nothing. Later but how they should look. Working with station in Vienna. The design, bearing tests in the university laboratory. visual inside-outside connection and solar the pavilion. We have two PhD students we got an email with a camera-phone famous architects can be important for which includes a high-level gain. The two basic parameters for the skin in the offi ce, one who’s concentrating on video of 1:1 prototype testing on site; that your portfolio, but you can be part of walkway and a cycle path, You are currently working on your largest were the size and the slope of the glass. engineering aspects of elastic deformation was one of the happiest moments of last interesting engineering projects with all links two previously separated project to date: a 1.5-km-long façade for We used ‘low tech’ digital tools that we and another who’s categorizing different year. They’re really building the pavilion! kinds of offi ces. city parks. the Bao’an Airport in Shenzhen, China, developed ourselves. In terms of handling plant movements and how they can be It’s a bit strange when you’re not there knippershelbig.com The project is a prime example which was designed by Studio Fuksas. such a degree of complexity, there’s no transformed into architectural forms. to learn during the execution of your of an integrated approach When the airport opens in 2014, it will magic formula, just a lot of hard work. I was trained to avoid structural design, but every project has a different to energy conservation (grey serve 40 million passengers annually. What failure at all costs – and buckling, in collaborative process. energy) and effi cient recycling, were your major engineering challenges? What else is currently in the works? particular – and here we are doing it. thanks to the systematic use The airport will have a shimmering, The Thematic Pavilion for Expo 2012 in [He takes a piece of paper and twists In 2009 you opened an offi ce in of large quantities of locally folded-aluminium and glass façade. The Yeosu, South Korea. We developed a it.] Highly complicated theories have New York City. What projects are available timber, which stores geometry is extremely complex. It has a kinetic façade with Soma Architecture, a been developed and calculations made being developed there? CO2 and costs relatively little free-form steel skeleton and a concrete young design offi ce in Vienna. They came to discover at what point buckling and Our New York work includes a project in to process. The bridge, with its substructure with a triple-layer structural to us with a rendering of their winning deformation start to happen. We went in a China with Grimshaw, a smaller project free-form frame of laminated system to support the internal 80-m-clear competition entry for the pavilion, which completely different direction from that of with Asymptote and a competition entry timber girders, uses a fraction span. In the simplest of terms, we took fl at features a moving façade. Together, we conventional engineering and designed a with Diller Scofi dio + Renfro. of the energy required for the sheet material and mapped it on a curved fi gured out how it could work, how it buckling form, which we used as a moving construction of a concrete or steel bridge of the same size. Renderings knippers Helbig

a gradient of less than 4 per cent offers users a gentle climb.

Site plan.

160 LoNg SeCTIoN STRuCTuRaL eNgINeeRINg 161 STuTTgaRT/geRMaNy kNIPPeRS HeLBIg Thematic pavilion peek & Cloppenburg Soma Architecture Renzo Piano Building Workshop Yeosu / South Korea Cologne / Germany 2012 (under construction) 2005

Viennese architecture fi rm A glazed dome tops Renzo Soma won the competition Piano’s concrete-framed for a pavilion to feature at Peek & Cloppenburg depart- South Korea’s Expo 2012. The ment store. Knippers Helbig fi rm asked Knippers Helbig to designed the façade, whose Louvres are made from fibre-reinforced engineer the pavilion’s imbricated skin consists of polymer, a strong, flexible plastic. each kinetic façade. 6,800 individual glass panes. louvre has one thinner and one thicker edge The building has two main Knippers Helbig wrapped and is equipped with actuators, top and façades. The waterfront the frame of the fi ve-storey bottom. These devices allow the louvres to compress asymmetrically, creating outward façade refers to pebbles, department store in a free- and sideward deformation and giving an and the kinetic façade, which form shell structure. Vertically impression of flaring fish gills. after boasts the main entrance arranged timber-lamella dark, LeD lighting increases the effect of and faces the event grounds, trusses and horizontally a living fish gliding through water. Photo Leonhard Coreth symbolizes the gills of a fi sh. running façade tubes are More than 100 individually attached to the shell with moving louvres can be diagonally spanned cables. programmed to respond to The lamellas are graded from the position of the sun and fl oor to fl oor according to the intensity of sunlight. The the strain. The Siberian-larch façade can also ‘perform’ to a trusses were completely choreographed program and prefabricated. The engineers react to individual events. attached the shell structure Renderings Soma architecture to the concrete frame at only a few rigid points, enabling Detail of diagonally an almost complete isolation spanned cables. of distortion forces. On the an interior view of the shell fourth fl oor, the façade shell is structure shows wooden members, attached by means of consoles. cables and attachments. Renderings knippers Helbig Photo Michel Denancé

162 LoNg SeCTIoN STRuCTuRaL eNgINeeRINg 163 STuTTgaRT/geRMaNy kNIPPeRS HeLBIg