A FORM-FINDING TOOL FOR POST-FORMED TIMBER GRIDSHELLS

Timber gridshells provide several advantages in terms of structural performance (due to their double curvature) and the efficient use of materials. With three-dimensional CAD software, it is now possible to model a free-form surface and discretize it in smaller straight elements, thus postponing the design of the node-connections geometry to the manufacturing process (i.e. by Computer-Aided-Manufacturing). A “low-tech” alternative of building free-form timber gridshell structures is that of assembling an initially flat grid using continuous elements connected with “simple” single-bolt connections and then, post-forming (bending) it in a double curved shape. Accordingly, this second method doesn’t require high-tech manufacturing processes. However, being the final shape influenced by equilibrium of the internal forces, a formfinding procedure will be required. The tool presented in this paper provides a practical solution to this problem. Starting from a “target” shape it is possible, together with nonlinear Finite Element analysis running in the background, to generate free-form shells made of continuous bent timber laths. Thus, the user will be able to explore different design solutions by simply changing the tools input parameters, without the need for time consuming scale models.