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Landesgartenschau Exhibition Hall

The Exhibition Hall is an architectural prototype building and a showcase for the current developments in computational design and robotic fabrication for lightweight timber construction.

The Landesgartenschau Exhibition Hall was conceived at the University of Stuttgart as part of the “Robotics in Timber Construction” research project.

The project demonstrates the new opportunities that arise from the integration of computational design, simulation and fabrication methods for performative and resource efficient constructions made from the locally available and renewable resource wood. The building introduces an innovative, robotically fabricated lightweight timber plate construction system made of beech plywood. It was developed at the Institute for Computational Design, the Institute of Building Structures and Structural Design, and the Institute of Engineering Geodesy and realized in collaboration with Mullerblaustein Holzbau GmbH. The building is part of the biannual Landesgartenschau, where it hosts an exhibition by ForstBW.

Landesgartenschau Exhibition Hall 2014 (© ICD/ITKE/IIGS University of Stuttgart) — Landesgartenschau Exhibition Hall 2014 © ICD/ITKE/IIGS University of Stuttgart

Wood is one of the oldest building materials known to mankind. But the advent of novel robotic fabrication processes in conjunction with computational design, simulation, and surveying methods, offers entirely new design possibilities and fields of application. These form the basis for particularly performative and efficient constructions made from the locally available and renewable resource wood. The following five main aspects highlight the project’s innovative character.

Biomimetic lightweight design: In comparison to man‐made constructions natural biological constructions exhibit a significantly higher degree of morphological differentiation. In the context of the Landesgartenschau Exhibition Hall, natural plate shells are of particular interest as they are a performative construction system made of individual elements. The skeleton of sea urchins is such a modular system made of calcium carbonate plates that are joined by microscopic interlocking projections along the plate edges that are very similar to man‐made finger joints.

Computational design and simulation: The computational design tool developed in the context of this research project offers the possibility to include material characteristics and fabrication parameters in the design process. Rather than drawing each plate manually, the plate’s design space is incorporated into a simulation and optimisation process for automated form‐finding, which includes parameters and constraints of robotic fabrication.

Robotic fabrication: A main focus lies on the coherent digital chain from the geometry generation to the structural analysis and digital fabrication. This includes the robotic fabrication of all 243 geometrically differentiated beech plywood plates for the primary structure, as well as the digital prefabrication of the insulation, waterproofing and cladding. One of the most important challenges and innovations is the robotic fabrication of the 7600 individual finger joints, which, through their interlocking connection, are the main reason for the building’s structural stability. Still visible in the building’s interior, the finger joint connections resemble the sand dollar’s microscopic connections and are only efficiently producible with a seven axis robotic fabrication setup. The industrial robot’s kinematic flexibility is an essential requirement for the production of such complex and individual geometries. Consequently, the fact that, similar to the sand dollar’s plate skeleton, all plywood plates are geometrically unique, poses no additional difficulties. Pre‐fabrication of the plate shell elements required only 3 weeks.

Advanced surveying methods: In comparison to conventional prefabrication methods, the developed fabrication technique allows for a much higher precision. Additionally, the finished building will repeatedly be scanned three‐dimensionally to analyse the structure’s long‐term behaviour. At this point, it was already possible to conclude that the plywood plate’s in‐plane mean square deviation, which is a measure for fabrication accuracy, is only 0.86mm. In comparison to tolerances in conventional timber construction, this is an exceptionally low value.

Innovative timber construction: The Landesgartenschau Exhibition Hall is the first building whose primary structure consists of robotically fabricated beech plywood plates. Similar to the functional integration in many biological systems, the plate system forms the building’s structure and envelope at the same time. The structural loads that occur around the plate’s edges are transferred efficiently by the robotically fabricated finger joints. This new kind of timber construction allows the building to be made of only 50mm thick plywood plates.

The Landesgartenschau Exhibition Hall is organized into two individual spatial zones that are differentiated through the building’s overall geometry: the entrance space and the main exhibition space. In both zones the plate structure is dome‐shaped consisting of convex polygonal plates. An intermediate space or transition zone is defined by a saddle‐shaped spatial contraction where the shell consists of concave polygonal plates. Visitors enter the building through the lower part of the shell and are guided through the slight narrowing of the structure to the 6 meters high main space with its large glass facade opening towards the surrounding landscape. The interior is characterised not only by its global geometry, but particularly by the plywood plates and their visible finger joint connections. The geometric gradient between convex and concave polygonal plates emphasises the spatial arrangement. The construction principles that were derived from the geometric differentiation of biological systems remain visible and become part of the architectural experience.