ReGrow

The research project "ReGrow – Digital Circular Construction: Innovating with Natural Materials" investigated and explored new applications for rapidly renewable regional materials in the construction industry by developing digital design and manufacturing processes for more sustainable and recyclable modular building structures. As part of the project, construction applications of natural fibres and fast-growing plant material were analysed, which can only be processed into load-bearing components through the use of specially adapted digital production technology. In addition to traditional timber construction, this expanded and diversified the range of locally available forestry and agricultural building materials, thus making an important contribution to the circular economy in the construction industry.

 

The ReGrow project (2022-2024), funded by the state government, was an interdisciplinary joint project of the five professorships of the Karlsruhe Institute of Technology (KIT): Digital Design & Construction (DDF), Design of Structures (dos), Building Physics & Technical Design (fbta), Light Technology Institute (LTI) and Institute of Industrial Management and Production (IIP) in cooperation with the industry partner FibR, to adress current challenges and opportunities around the use of natural resources such as fibres, wood and earth-based materials in architectural design and robotic manufacturing. It questions current production methods and gives an outlook on digital circular building.

 

The project focused on three digital and circular construction processes for renewable materials:

 

• A robotic free-form winding process for the use of natural fibres in load-bearing construction applications was expanded and adapted in order to implement lightweight structures in the future that are not only extremely material-efficient, but at the same time based on renewable raw materials.

 

• An application for robot-assisted 3D willow weaving was developed for structural applications. This includes both the development of a new type of construction and design repertoire and the realisation of corresponding machine technologies for the production of load-bearing components. Both technologies are combined in a complementary way and supplemented by the building material earth in order to realise a modular concept for the production of functionally integrated components made from renewable raw materials. The hybrid construction system combines the tensile strength of willow with the compressive strength of clay in a sustainable material system as a structural analogue and ecological alternative to reinforced concrete.

 

• An alternative fabrication method to standardized glue-laminated timber for large-scale free-form architecture. This is done through mechanical lamination of elastically bent timber lamellas, which is a smart yet simple form-giving strategy, completely independent of moulds, pneumatic presses and glue, which is often entailed in the contemporary production of curved glue-laminated timber.  

Two construction demonstrators were presented at the 2023 Federal Garden Show (BUGA23) in Mannheim (Germany). The first research building “REGROW TIMBER CANOPY” made of robotically wound structural flax fibre columns and wooden lamellas were used to create a shading and roofing structure that provided a venue for lectures and exhibitions. “REGROW WILLOW” the second demonstrator building showed the use of the historical composite material of willow and clay in a digital reinterpretation using sustainable design and production processes. The willow-clay research prototype was expanded to include integrative approaches for local energy generation and improvement of the local microclimate. Corresponding information events, visitor surveys and an international symposium at the Federal Garden Show were used to provide a large audience with an insight into the topic of digital, circular and sustainable construction.