24.08.2021, At the IASS 2020/21 Annual Symposium and SURREY 7 International Conference on Spatial Structures, Christopher Robeller presented the paper entitled “HexBox Canopy: A Segmented Timber Plate Shell with Hardwood Wedge Joints”, authored by Christopher Robeller, Eduardo de Oliveira Barata, Enrico Valentino Tagliaboschi, and Felix Schmidt-Kleepsies.
Abstract: The HexBox Canopy demonstrates a new “plug & play” system for the rapid on-site assembly and disassembly without formwork of a segmented timber shell, consisting of relatively inexpensive, prefabricated hexagon-shaped boxes made from plywood plates. With 1531 timber segments making up 201 boxes, the HexBox shell is made exclusively of plywood components without the addition of any kind of metal fasteners for the main load-bearing structure. The major novelty is the wood-only connections between the box components, which are produced from cut-off waste material resulting from the cutting of the main plates of the structure. These connectors are inspired by traditional wedge joints, which were a smart and common method in handcrafted carpentry and cabinetmaking. Rather than attempting ultra-precisely fabricated elements, the wedges allow assembling box-like segments even when there are small imprecisions. Additionally, these joints allow for pulling and forcing the boxes together, closing gaps between the elements which may occur during assembly. Another key aspect is the introduction of an innovative technique that allows for the simple and safe 1K PUR adhesive joining of thousands of miter joints with individual dihedral angles. Conventional clamping tools are indeed designed for orthogonal miter joints and could therefore not be used here.