“Digital design and fabrication at the companies Schlaich, Bergermann und Partner and Buro Happold“

Illinois Institute of Technology Digital Design and Fabrication Spring 2006 Student: Simon Fiedler Research Paper - Arch 497 Digital Design and Fabrication

Digital design and fabrication at the engineering companies Schlaich, Bergermann und Partner and Buro Happold

Contents

1 Introduction – the importance of digital design 3

2 Schlaich Bergermann und Partner

2.1 The office 4 2.2 The philosophy 4 2.3 The projects and the use of digital design tools 2.3.1 Solar Chimney 6 2.3.2 The roof for the atrium of the DZ Bank 7 2.3.3 “Lehrter Bahnhof” train station 8

3 Buro Happold

3.1 The office 9 3.2 The philosophy 10 3.3 The use of digital design tools 3.3.1 Knowledge share and development groups 11 3.3.2 Software packages 11 3.3.3 In-House software 12 3.3.4 CoSA solutions 13

4 Conclusion – a comparison of the two engineering firms 14 References 16

- 2 - 1 Introduction – the importance of digital design

Within the last twenty years the design process in architectural offices as well as in engineering companies changed completely. With the beginning of the digital age computer started to remove the drawing tables from the offices. CAD software was developed first of all to improve the efficiency of the design process, to save time and money and to minimize errors that could happen with hand drawings. The further development of CAD solutions tried to optimize the data transfer from program to program that is still a problem till this day. Today a project is almost impossible to realize without digital design and there are a lot of projects that would have been just unbuildable without digital design tools. The use of 3D models is getting more important. Engineers are using special software to analyze, to check and calculate the buildability of a structure and to optimize their shapes. For example double curved surfaces are built and optimized completely on the computer before the data can be sent to a Laser Cutter Machine that cuts every single element from a plate. The importance of Digital Design is very high nowadays and could still increase. This research paper presents the companies of Schlaich, Bergermann und Partner and Buro Happold. The paper focuses on the topic of digital design, their tools, their use in engineering companies and their influence in the design and design process.

- 3 - 2 Schlaich, Bergermann und Partner

2.1 The office

Schlaich, Bergermann und Partner (SBP) is a structural consulting engineering firm founded in 1980 by Jörg Schlaich and Rudolf Bergermann in , Germany. Jörg Schlaich who studied and became an authorized proof engineer in 1970. He worked together with Rudolf Bergermann who finished his studies in Civil engineering in 1966 in the office of Leonhardt und Andrä in Stuttgart before they decided to establish their own engineering firm in 1980. Today the firm has got, beside the two founders, eight partners and about 60 employees working in offices in Stuttgart, and New York. Based on the size of the company SBP is able to act in all different fields including wide-span lightweight roofs, bridges, slender towers, hi-rise structures, sports facilities and innovative solar energy power plants. All the projects are founded on a philosophy the office gives “to contribute to the building cultures”.

2.2 The philosophy

“The art of building is indivisible” is a statement on the webpage of Schlaich, Bergermann und Partner. The knowledge of all structural types and all materials is important to design, analyse, check or supervise the projects. Furthermore the cooperation with architects, engineers and contractors is significant. As a partner of the planning team SBP assist the employer or the architect in the search for the best solution for the task at hand. The ambitions are “efficiency, beauty and ecology”. This describes the work on several fields to design innovative structures. Similar to a kitchen sieve SBP developed a possibility to create double curved structures. Based on a plane

- 4 - square wire mesh a double curved surface can be created just by changing the angles on the nodes. An efficient structure can be formed with slender steel slats and thin cables that stiffen the . Another efficient invention is a so-called “spoked wheel”, a possibility to stiffen cooling towers or chimneys as well as cylindrical light-weight glass roofs. A rim stiffened by thin prestressed steel spokes becomes a “transparent diaphragm” and builds together with the construction itself a very light roof, i.e. for the atrium of the DZ-Bank in Berlin. A different contribution to the building culture is the research to develop solar energy utilisation and to produce environmentally clean energy. From large solar chimneys to small Dish/Stirling systems SBP built, builds and will build power plants to generate renewable energy in the future. The use of all existing technologies helps to translate the philosophy and theory into good, efficient and ecologic architecture. Digital design is an important part in the design process of every project. Computers are used for design proposals, wind or deformation analysis and for innovative future projects to reach the desired result. The design tools, the devices and the software the company uses will be presented in the following parts with three given projects done by Schlaich, Bergermann und Partner.

- 5 - 2.3 The projects and the use of digital design tools 2.3.1 Solar Chimney

The first example is Solar Chimney, a solar tower power plant that is expected to be built in 2008 in Mildura, Australia. The concept of that innovative design contains a circular glass roof about 7000 meter in diameter open at the circumference that heats air underneath it. A thousand meter high vertical tower with large air inlets and a turbine at its base stands in the center of the glass roof. The lighter hot air rises up the tower and propels the wind turbine. The energy of the airflow is converted to mechanical and afterwards to electrical energy to produce about 200MW of renewable energy. At first, the concept was completely developed with computer and software support. 3D models were created to present the design proposal to contractors and investors. Furthermore digital design tools were used to analyze the airflow and to optimize the shape and size of the glass roof and the chimney. Problems with wind turbines in tubes had to be analyzed, because the air is slower after passing the turbine and so the effectiveness of the turbine has to be verified in the chimney. CFD software was also used to maximize the efficiency of power plants by analyzing and optimizing the shape of the wind turbine. Later in the design prototypes were built also to test the efficiency. The wind turbines were tested in wind channels and the first small power plant was built in Manzanaras, Spain. A long term test was made to prove the concept designed on the computer and partly analyzed with prototypes.

- 6 - 2.3.2 The roof for the atrium of the DZ Bank

The design for the roof of the DZ Bank in Berlin, Germany, was done in cooperation with Gehry architects. The teamwork and the data transfer was one important part to get a successful result of the proposal. Therefore Schlaich, Bergermann und Partner is very flexible in the use of digital design tools. Dependent on the employer or architect the engineering firm reacts and chooses the software package to minimize data loss between the contractors, designers and engineers. Usually SBP draws on AutoCAD or on Nemetschek Allplan to cover the most needs and to minimize problems with data share. This project, a sculptural double-curved freeform glass-covered grid shell with triangular meshes including spoked wheels in 16 meter intervals to provide stiffness, was designed in CATIA V5. First of all a physical model was built and scanned by a 3D scanner. The data was imported to CATIA to develop the shape. SBP used several software programs to create and analyze the roof. The grid shell was optimized to minimize the amount of different nodes and angles and to improve the angles for the vertical loads and their way to the foundation. FEM analysis was made to check the deformation. Neither the development of the design, nor the calculations nor the construction would have been possible without the help of the digital devices. The grid shell was manufactured with Water Jet technology. Every single different node was cut out of 70mm thick stainless steel plates.

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2.3.3 Lehrter Bahnhof train station

Another project of Schlaich, Bergermann und Partner is the “Lehrter Bahnhof” train station in Berlin, Germany. Architect for that design is Gerkan, Marg und Partner. SBP did the conceptual design, detailed design and site supervision for the glass roof of the platform. The concept shows a smooth curved train station covered with a glass roof with a maximum span of 65 meter over a length of 430 meter. The roof section corresponds with the requirements for train clearance resulting in a flat area at the top of the hall and a steep area at the roof support. The double-curved surface is created by a quad-angulated grid shell with squares about 1.65m x 1.65m. The stiffness is provided by thin cables and by cable trusses that span over the tracks. Especially these trusses are developed with analyzing software. SBP uses programs of the SOFISTIK Company. SOFISTIK offers software for structural and civil engineers that provide FEA & CAE solutions for building-, bridge- and steel design, tunnelling, soil-engineering, dynamics, membranes and fluid dynamics (CFD). SOFIplus is a design program that can be purchased either as a software package or as an add on for AutoCAD. It is 100% AutoCAD compatible, uses all AutoCAD commands and increases the possibilities of AutoCAD. Among other things it offers an automatic distribution of loads along any line, curve or spline. Furthermore a Freeform- Surface option and an automatic mesh generator are included to model

- 8 - almost any 3D structure. DWG/DXF In-/Export opportunities give the user the possibility to exchange the data with other programs or people. The analyzing tool used for the “Lehrter Bahnhof” project is ASE, a 3D Finite Element Analysis program. Eigenfrequency analysis can be done as well as special FE-analysis of light shell structures to avoid bending stresses and also to find the best form. With the time step method a fourth dimension can be added to analyze time dependent effects. In this case the shape for the cable trusses that follow the moment diagram were optimized and developed. STAR 3D, a 3D frame system analysis software of SOFISTIK, was also used in this project to accomplish a material based deformation analysis. In general Schlaich, Bergermann und Partner uses a variety of software programs to find the best way of cooperation with architects and engineers.

3 Buro Happold

3.1 The office

Similar ways of work, but also different ideas to take advantage of the digital design can be found at Buro Happold, the other engineering firm that will be presented in that research paper. Buro Happold was established in 1976 by Sir and six other engineers in , UK. They worked together at Ove Arup and partner where Edmund Happold was leading the prestigious group known as Structures 3. An offer to take the chair at the University of Bath as professor of Architecture and Engineering Design directed the way to open up an own office. Today Buro Happold

- 9 - employs about 1000 people in 13 offices in four continents including all engineering tasks like road schemes, bridges, sports stadia and tall buildings.

3.2 The philosophy

With their work Buro Happold wants to build a better, more efficient and sustainable architecture using new methods of construction, new materials and new technologies. Similar to Schlaich, Bergermann und Partner, Buro Happold gives

“principles of care, value and elegance” that builds a philosophy for the office. The projects could be separated in three main parts: Buildings, Infrastructure and Environment. In every single project the engineering approach will be seen as holistic that combines different disciplines and many contractors to one, integrated team. The cooperation between these teammembers within the office, but also between different contractors is a very important part for the design process. To improve the teamwork Buro Happold claims for knowledge share. In different in-house groups new developments are done and presented, new software that improves the desired result are coded and Buro Happold is participating in many organizations to develop new technologies, to test new ways of designing or to improve the cooperation between architects, engineers, developers, manufacturers and other contractors.

- 10 - 3.3 The use of digital design tools 3.3.1 Knowledge share and development groups

“Buro Happold is an open-learning organisation that attaches a great deal of importance to gaining and sharing knowledge. Lessons learnt from projects, conferences and professional meetings are disseminated through in-house presentations, talks and site visits, as well as through the company’s intranet”. Based on a Design and Technology Board (DTB) to nurture and develop our intellectual assets in terms of product, design and service development several development groups extend their knowledge by creating new ideas, new methods or new technologies. Discipline development groups are researching in their field and often within one project on specific topics. The results are presented to the office. The development of new techniques, technologies and services is part of the in-house Research, Development and Innovation group (RDI). Annually one percent of the turnover is reinvested into RDI activities. Together with industry partners, universities, research organizations or public bodies Buro Happold works on collaborative research. Especially the field of new computer technology like the use of single-building model or the programming of new software that could improve the efficiency of desired results in analysis is a significant part of the research.

3.3.2 Software packages

Buro Happold uses a huge variety of software packages available on the commercial market. Before other software companies started to offer solutions the office has also been written their own parametric geometry generation routines to generate architectural forms. Now there are commercial packages that simplify the interoperability with other offices. Depending on the software architects and other contractors are using, Buro

- 11 - Happold chooses their software for every project and tries to find the best solution for every single problem. That’s the reason why not an exactly list of used software can be given. Software also changes a lot within a short period of time. New programs come on the market that can maybe solve a specific problem the other software couldn’t solve. In general Buro Happold uses AutoCAD, Microstation or CATIA on the CAD side with several Add-ons for specific tasks like 3D+ and x-steel for interfacing with contractors and manufacturers or specific software for parametric rule-based modelling. Revit for AutoCAD, Generative Components for Microstation and Digital Project for CATIA are the programs for this job. The structural analysis is done on many programs as the project dictates. Some of them are more general in use like Robot Millenium or StaadPro / Qse others are more specialist like ANSYS & CFX for high end analysis or for more specific building types like Multi-Frame, ETABS or Rapt. The named software programs are just examples among a long list of other analyzing solutions. A group of people of the RDI group is in charge to keep the software up to date, to find for every project the right software package and to purchase new software if necessary. This group also develops the own in-house software, if the project or a problem ask for a solution that can’t be solved by programs that are available on the commercial market.

3.3.3 In-House software

The first and most historic software of Buro Happold that is still in use is Tensyl Suite, a dynamic relaxation form finding program for cable and fabric structures. The generation and the analysis of structures can be done in that program and will be optimized by calculations the software does to find “minimal” surfaces or high in-plane forces. Complex double curved

- 12 - structures and every single member of that construction can be analyzed and generated with that program.

Another very useful tool to generate curved surfaces and to create data that can be used for the manufacturing is SMART Form. This program allows the user to optimize meshes in two ways. The first possibility is to get mesh parts with the same length by finding all possibilities, changing angles and using kinematic mapping. The result is a very efficient and economic mesh that has members with the same size. The other opportunity this program offers is a tool that divides a double curved surface into a mesh that includes only plane surfaces by using geometric mapping. A construction pattern generator creates a two dimensional surface of the former double curved three dimensional object by unfurling the mesh into a flatten surface. This data now can be transferred to the manufacturer that can directly send the data to a Laser Cutter or another cutting machine to create the object.

Furthermore Buro Happold has also developed software to analyze a wide variety of specialist problems such as people-flow modelling, CCTV camera optics, 3D geometry modelling and penalization.

3.3.4 CoSA solutions

A special building analysis group called CoSA solutions (Computational Simulation and Analysis) uses this kind of software for their analysis and - 13 - research. CoSA is in charge to test and quantify the future performance of a building while it is still in the design phase. Aspects such as external wind effects, thermal and environmental performance, energy consumption, internal airflow and fire and smoke movements are analyzed by using sophisticated 3D computer simulations to optimize the result the building should be and to give the opportunity to change the proposal already in the design phase before construction costs are incurred. Improvements in the design process as well as new shapes and expressions by using modern materials and new construction methods can be done with the advanced analysis tools to deliver more integrated, economical and sustainable buildings. To reduce energy usage CoSA analyzes all aspects of the building fabric and systems, including natural ventilation and solar shading systems, orientation and plant design.

4 Conclusion – a comparison of the two engineering firms

Buro Happold is an important company that tries to optimize and improve the cooperation between architects, engineers and the industry. With their research within the office and their research in different organizations, they contribute to the progress of digital design and their use in architectural and engineering firms. Organizations ask Buro Happold to participate as an engineering partner on research projects or on case studies. With a huge variety of software packages Buro Happold is qualified as a strong partner in every project and all including structural tasks. Similar to Buro Happold, Schlaich, Bergermann und Partner also tries to optimize the interoperability between all participating parts for every project. By using design tools in a big variety SBP finds the best solution and the best software cooperates with the other contractor or architect. A comparison on the field of research is not possible, because the office size between Buro Happold and SBP differs greatly.

- 14 - However, it could be said that SBP with their office and infrastructure optimizes the cooperation with architects to be involved by building the architecture of tomorrow. Buro Happold is able to be seen as a strong partner on the structural and analytical side. With their own in-house software and several research groups they offer possibilities to architects, investors, industry and developers to create the architecture of tomorrow. While SBP is looking for partners and projects to offer their work, contractors come to Buro Happold to get the opportunity to use all the infrastructure and digital design tools the office has to build a modern, efficient and sustainable building.

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References:

Books: - The Solar Chimney, Jörg Schlaich, Edition Axel Menges, Stuttgart, printed in Stuttgart, 1995. - Leicht Weit light structures, edited by Annette Bögle, Peter Cachola Schmal, Ingeborg Flagge, 2nd revised and expanded editon 2005, Prestel Verlag München, 2003. - Happold, the confidence to build, edited by Derek Walker and Bill Addis, Happold Trust Publications Limited, 1997.

General webpages: - Official webpage of Schlaich, Bergermann und Partner: www.sbp.de - Official webpage of SOFISTIK AG: www.sofistik.com - Official webpage of Buro Happold: www.burohappold.com

Specific articles and webpages: - article about CoSA solutions: http://www.raeng.org.uk/news/publications/ingenia/issue17/Stribling.pdf - pdf case study about using single-building model: http://www.itconstructionforum.org.uk/uploadedfiles/027long.pdf - pdf presentation about the in-house software at Buro Happold: http://www.textiles.nottingham.ac.uk/Workshop2005/PShepherd.pdf

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