The Clay Rotunda is a cylindrical, free-standing structure that encloses the SE MusicLab, a high-fidelity music space inside the renovated Gurten Brewery in Bern. This innovative design uses unreinforced clay, a zero-waste, eco-friendly material, as its primary component. Standing 5 meters tall with a diameter of almost 11 meters, the structure was built entirely on-site over a period of 50 days using advanced robotic technology, assembling over 30,000 soft clay bricks.
The project was initiated by SE MusicLab, a high-fidelity music studio, with the design executed by a collaborative team involving experts from Lehmag (a specialist in earthen construction), Seforb (an engineering firm), and Brauchli Ziegeleien (a brick manufacturer). These partners share a commitment to integrating traditional materials with modern technology, striving to create sustainable, emission-free construction methods. Their collective goal was to push the limits of earthen architecture by blending computational design with ancient building techniques.
Design Concept
The slender form of the rotunda is stabilized by its undulating surface, which increases the footprint and prevents structural buckling. The geometry was carefully calculated using a computational model that integrated engineering requirements, material properties, and the construction process itself. Given the limited reach of the robotic arm and the natural shrinkage of clay as it dries, the structure was divided into trapezoidal sections. This segmentation was key to ensuring that each clay cylinder was positioned correctly and supported the structural integrity of the whole.
Material Innovation and Construction Process
To achieve the desired strength and malleability, a specific clay mix was developed, blending clay with sand, small stones, and water. This mixture was molded into cylindrical “soft bricks,” each 9 cm in diameter and 15 cm in height. A robotic arm then precisely placed and compressed each brick, reducing it by 40% of its height to create strong bonds between the units. The entire structure was built segment by segment, with the robot relocating to different positions as the project progressed. Throughout the process, 3D scanning was used to continuously monitor the structure’s geometry and adjust for any material shrinkage. Cracks that formed during drying were filled to maintain a consistent finish.
Sustainability Features
One of the key aspects of the Clay Rotunda is its commitment to sustainable building practices. By using clay, a natural material that can be recycled and returned to the earth, the project minimizes waste and avoids harmful emissions. The clay’s inherent qualities also contribute to the building’s interior climate, naturally regulating temperature and humidity, reducing the need for mechanical systems. This project pushes the boundaries of how traditional materials like clay can be reimagined through digital design and robotic construction.
Citations
- SE MusicLab Clay Rotunda. SE MusicLab, 2021, www.semusiclab.ch/project-clay-rotunda.
- Lehmag, Seforb, and Brauchli Ziegeleien. Clay Rotunda Process Report. SE MusicLab, 2021, www.semusiclab.ch/research-clay-rotunda.
- Lehmag. Earthen Construction Techniques in Contemporary Architecture. Journal of Sustainable Building, 2021, vol. 32, no. 4, pp. 50-65.