Additive robotic assembly techniques for timber construction (ARTC) – towards circular building construction with reused materials

Construction is facing a momentous challenge as it is one of the leading CO2 emitters and consumer of materials. Among other research, this proposal identifies three important strategies to counter this problem: Material efficiency, the use of renewable materials and the reuse of materials for building components. A combination of these strategies allows to use as little resources as possible, integrate materials in construction that store CO2, and create new circular value chains for construction materials, that nowadays are mainly deposited. This project proposal is a follow-up of the DFG research project "Additive robotic assembly techniques for timber construction", that investigated material efficient computational design methods in relation to robotic fabrication technologies. Robotic assembly and wood-only joining techniques were developed for lightweight hollow components. Unlike conventional timber flooring systems, a new type of hollow core timber slab system uses short timber beams in structurally optimised layouts between two layers of thin panels. Modern timber construction systems such as CLT rely on glued joints, making the resulting components difficult to recycle. In this project, we developed both fully automated and glue-free joining methods using robotically inserted beech dowels oriented at different angles to withstand both shear and tensile forces. This new proposal aims to address the third strategy, the reuse of construction materials. In Germany, millions of tonnes of waste wood are being generated as a result of recent legislative changes that end subsidies for energy recovery. As these materials come in a various sizes and material qualities, they have often been too technically challenging to integrate into industrial manufacturing systems. The design and fabricating methods, developed in the previous project, provide a good starting point, as there is no need to rely on standard beam and panel lengths, as the lightweight system is theoretically infinitely extendable. Even the top and bottom panels of the hollow core can be assembled from a variety of small elements and still provide a structural component. To deal effectively with varying material dimensions and qualities, this project aims to develop a new combined technology of robotic analysis, material preparation and fabrication. Computational design methods will be explored to assemble these irregular materials into components and spatial configurations consisting of slabs and walls for typical multi-storey timber buildings. Subsequently, different structural analysis and optimisation methods are investigated to design material efficient structures. We will build on the previous project to develop joints that can adapt to irregular materials and processes.

DFG Programme Research Grants