Double-layered timber plate shell

Abstract

This article presents a new lightweight construction system for doubly curved shells made from timber plates, inspired by the masonry vaults of Eladio Dieste. The system was developed for a specific case-study project, and general applications to other freeform surfaces are being discussed. The shells are built from two interconnected layers of structural wood veneer plates, using integral through-tenon joints for a fast, precise, and simple assembly. This allows for the construction of a series of differently shaped vaults without a costly mold or support structure. Instead, inclined joints cut with a 5-axis computer numerical controlled milling machine embed the correct location and angle between plates into the shape of the parts. This constrains the relative motions between joined parts to one assembly path. To take advantage of the benefits of such connectors, the constrained assembly paths must be considered in the fundamental design of the system, allowing for the insertion of each plate. This imposes additional constraints in the segmentation process of doubly curved shells. In order to meet the requirements and resolve the multi-constraint system, we use a global, nonlinear optimization approach. Developed as a close collaboration between architects, computer scientists and structural engineers, this article includes an experimental analysis of the influence of parametric modifications in the shape of connectors on their load-bearing performance.

Structural behaviour of folded timber sandwich structures

“…Double-layer folded plate structures with double through-tenon joints allow direct edgewise connection between four plates at any given fold, generating a greater resistance to bending moments [31,32]. Timber plate shell structures replace a folded geometry with a double-layer shell surface built up from integrally-attached timber boxes [33,34]. Direct moment loading of edge joints is reduced in the structure, as moment transmission resolves as a force couple, with compressive and tensile membrane action through box face plates.…”

Structural performance and digital fabrication of low-cost folded sandwich structures

“…-Mechanical joints were fabricated using 7-axis robots. Double-layered timber plate shell structure [55,76] Throughtenon joints -The prototype structure was constructed from 15mm birch plywood panels. The full-scale structure was constructed from 40mm LVL plates.…”