Asymptotic Geodesic Hybrid Timber Gridshell

Abstract

This paper presents a strategy to design and build strained timber gridshells from exclusively straight timber planks, which are interwoven and elastically deployed into a doubly curved web. For this purpose, we combine asymptotic (A) and geodesic (G) curves into hybrid AAG-webs on curved surfaces.We present a digital method to design and geometrically optimize the timber AAG-webs to include equal intersection angles and geodesic boundaries. This new construction system benefits from the targeted use of the two differing bending axes of timber planks for flexibility and rigidity. The flat geodesic planks are interlaced at the midpoint of the asymptotic beams to create a tri-hex pattern, which lowers the buckling length and decisively increases the overall stiffness. As a proof of concept, a large-scale timber gridshell covering an area of 60m2 was designed and built.We document the construction process of manufacturing, prefabrication, elastic deformation, on-site assembly, and installation of the polycarbonate cover to verify constructive tolerances and feasibility. The structure is tested and simulated to validate our computational results.