New thinking

The famous Stuttgart architect Frei Otto once revolutionized the design process of buildings with his principle of finding forms. Now another revolutionary innovation from Stuttgart is set to emerge: co-design, the digital networking of planning, building processes and building systems. One of the progenitors of this method is Professor of Architecture Achim Menges. Together with more than 100 scientists at the “Integrative Computational Design and Construction for Architecture” Cluster of Excellence, he wants to make the predigital building industry fit for the future.

A certain dissatisfaction with the state of affairs is often the beginning of new progress. Achim Menges already felt this dissatisfaction in the 1990s: When the current professor and director of the Institute for Computational Design (ICD) at the University of Stuttgart studied at the TU Darmstadt and later at the Architectural Association in London, “blob architecture” or “free-form architecture” with its seemingly organic forms was regarded as forward-looking, as it had only just become possible with the advent of computer-based planning (CAD). “I was irritated by the fact that although the buildings looked different, the planning methods were relatively conventional,” recalls Menges. “I was particularly surprised by the fact that the ambitions were always related only to design and planning and that there was a discontinuity when it came to materials usage and construction.”

The construction process was essentially the same as before, but with digital support. Menges, on the other hand, was interested in the question of how digital technologies could be used to combine planning and construction to derive a completely new form of architecture. Today, 20 years later, the 43-year-old has made good progress along this path, which is evident in two pavilions on display at the Federal Horticultural Show (BUGA) 2019 in Heilbronn. Menges and his team designed and built them together with the Institute of Building Structures and Structural Design (ITKE) under the supervision of civil engineer Prof. Jan Knippers. They are the latest in a series of visionary works that the interdisciplinary team sets up year after year in Stuttgart's Stadtgarten. It is important for Menges to emphasize that building and architecture are never about the performance of a single individual.

Like many of the researchers in Stuttgart, he regards Frei Otto as one of his influences. The current research generation around Menges and Knippers has transferred his form finding process, which he developed in Stuttgart, into the digital age. While the architect, who died in 2015, still covered simple wire models with soap film to find the perfect shape for the tent roof of the Munich Olympic Stadium, scientists today use digital techniques. Among other things, they use them to translate nature's complex construction principles into lightweight structures that would not otherwise be possible in the same way: a spider was the inspiration for one of the former pavilions made of fiber composite materials. The wooden forest pavilion built for the Landesgartenschau Schwäbisch Gmünd 2014 was modelled on the shell of a sea urchin, the sand dollar.

Computers are now bridging the discontinuity that disturbed Menges in the late 1990s by introducing feedback loops: “We try to think holistically and to create digital feedback loops between design and planning methods, manufacturing and construction processes as well as material and construction systems from the very beginning. We ask ourselves: what new building systems and construction methods can emerge that are genuinely digital?” Menges calls this principle co-design. 

The researchers developed a fully automated production system for the timber pavilion for BUGA 2019 at the same time as creating the design methods. Two robots produced 376 geometrically different hollow cassettes from veneer layer boards. One robot takes a thin wooden plate and places it on a holder. The second applies glue all around. The first machine then places a ring beam along the edges, the second nails it with wooden nails. Then the surface panel is applied following the same principle. Finally, the robots cut box joints along the sides, which enable the pavilion to be pieced together like a 3D puzzle.

In the same way that planning, material and production interlock, the computer had previously calculated the geometry of the plates itself by, among other things, reconciling the dimensions of the structure with the limits of the robotic arms and the mechanical properties and dimensions of the beech wood, always under the proviso that as few panels as possible were to be produced and that they should be as lightweight as possible. Menges explains that the declared goal was to surpass Schwäbisch Gmünd's own pavilion. The new one is three times as large without increasing the base weight of 42 kilograms per square meter. “This was only possible because we were no longer building with solid panels, but with hollow cassettes.” Without an automated system, such a construction method would not be manageable - at least not economically and within twelve months. The concrete planning began only one year before the completion of the pavilion for the opening of the Federal Horticultural Show.

The principle of co-design is even more obvious in the fiber pavilion on display at BUGA 2019. The 60 individual elements of this exhibition piece were created practically in open space. A robot wrapped the glass and carbon fibers around two distantly spaced frames. The synthetic resin on the fibers hardened enabling the resulting element to be removed from the holder and installed. Each has a different shape, geometry and fiber arrangement depending on the prevailing forces and architectural requirements. This enables a surface weight of just 7.6 kilograms per square meter of load-bearing fiber construction for 400 square meters of spanned area. A transparent ETFE film makes the pavilion weatherproof. Both constructions meet all German building standards and structural requirements. “The pavilions provide a glimpse into the future of construction. The technology is ready,” says Menges.

According to Menges the goal of the Integrative Computational Design and Construction for Architecture Cluster of Excellence of which he is the spokesman, is “to further develop this technology for the broad mass of building applications”. From 2019 to 2025, the University of Stuttgart will receive funding of several million euro per year from the German Research Foundation (DFG). More than 100 scientists from seven faculties and from the Max Planck Institute for Intelligent Systems now want to transfer co-design to the building industry. In addition to architecture and civil engineering, other disciplines involved include construction physics, engineering geodesy, production and systems engineering, computer science and robotics, as well as the social scientists and humanities. The researchers will develop digital and at least partially autonomous construction processes in three networks: for multistory construction, for existing buildings and for wide-span buildings. “It is about research into integrative, computer-based design and planning methods, about new manufacturing and construction processes, about genuinely digital building systems of the next generation. And thus also about a new kind of construction work that will change architecture,” says Menges.

In just three years, each of the three networks will have realized a first prototype building, with a second following in 2025. Because time is of the essence: “Our current construction methods place a massive burden on the planet,” he says. They consume 40 percent of global resources and energy. What's more, they generate 50 percent of the world's waste. At the same time, the number of buildings worldwide will have to double by 2050 - not only due to population growth, but also because of global urbanization. In view of these prospects, the visionary speaks into the conscience of his guild: “Neither our methods nor our construction processes or styles are suitable for this.” In terms of digitization, the construction industry currently occupies the last place of all branches of industry - behind forestry or fishing. Productivity has even fallen recently. It is high time for real progress in construction. And once again it should start in Stuttgart.

Daniel Völpel