Reciproframe: A Hybrid Trivalent/Reciprocal Frame Construction System for the Low-Cost, Material-Efficient, and Rapid Assembly of Reusable Timber Gridshells.

This poster proposes a new beam topology enabled by the precision and speed of modern, computer-controlled joinery machines. This allows for free-form shapes such as structurally-efficient catenary cross-section, without the need for any steel nodes, which were not possible with previous geodesic domes such as the Tacoma Dome (1983), Saldomel and Saldome2. The system combines the use of planar hexagonal facets (P-Hex), which allows for a Constant-Distance offset (COO) of the polygonal frames, with a reciprocal cross-bracing that offers simple, but structurally efficient, joints. As a result, a hybrid timber system was achieved through a combination of a primary topology of wooden beams in a trivalent configuration, and a secondary set of cross-bracing beams. This poster presents the applicability of the construction system on a medium-scale research demonstrator with a maximum span of 15 meters, made of 768 industrially-fabricated laminated veneer lumber LVL beams. Compared to a cross-laminated timber CLT plate version, the system is 100% reusable, 100% adhesive-free, 55% lighter, and 98.5% material-efficient, while having almost the same structural behavior.