Researchers and students from the Universities of Freiburg and Stuttgart designed a lightweight pavilion made from robotically wound flax fibres.

The construction industry is one of the most material-intensive and environmentally detrimental human activities. With their pavilion called livMatS, the researchers aim to offer a viable, resource-efficient alternative to conventional construction methods. To do so, they use flax, a naturally renewable, biodegradable material that is regionally available in Central Europe.

Fibre composites have great strength-to-weight ratio, which makes them very suitable for innovative, material-efficient lightweight structures. Carbon and glass fibre reinforced materials are already widely used in various fields, from aerospace engineering to the automotive industry. However, while natural fibres like flax have comparable mechanical properties, they are not often considered as building materials.

livMatS is said to be the first building ever with a load-bearing structure that is entirely made of robotically wound flax fibre. It combines natural materials and advanced digital technologies to create unique architecture “that is at the same time ecological and expressive”.

The pavilion was inspired by the saguaro cactus (Carnegia gigantea) and the prickly pear cactus (Opuntia sp.), which are characterized by their special wood structure. The saguaro cactus has a cylindrical wooden core that is hollow inside and thus particularly light. It consists of a net-like wooden structure, which gives the skeleton additional stability and is formed as a result of the intergrowth of its individual wood elements.

The tissue of the flattened side shoots of the prickly pear cactus is also interwoven with net-like wood fibre bundles, which are arranged in layers and interconnected. As a result, the tissue of the prickly pear cactus is characterized by a particularly high load-bearing capacity. By abstracting these network structures, the scientists were able to transfer the mechanical properties of the cross-linked fibre structures to the lightweight structural elements of the pavilion.

The load-bearing building elements are produced with a coreless filament winding process developed by the project team. In this additive manufacturing approach, a robot very precisely places fibre bundles on a winding frame. This allows for the targeted calibration and architectural articulation of the orientation, alignment, and density of the fibres to fit exactly the structural requirements in the component, as in its biological inspiration.

The elements vary in overall length from 4.50 to 5.50m and weigh only 105kg on average. The entire fibre structure weighs approximately 1.5t while covering an area of 46m². The final design complies with the German building code and related structural permit requirements and set of load combinations including wind and snow loads.

Photos: ICD/ITKE/IntCDC University of Stuttgart