Parametric design for the structural elements of timber rib shells

The presentation reveals a new method for determining the layout of the structural elements for timber rib shells, using parametric design.

The author has developed a computer program that generates lines of single curvature over any given surface. The goal was to provide a tool for simplifying the design process of ribbed timber shell structures built from a grid of planks running flush with the surface and, given the nature of a plank, curved in one direction only. Finding the correct geometrical layout of the structural elements is crucial for the construction of rib timber shells, hi addition, it is beneficial for other methods of construction using curved surfaces. Currently, adequate computer tools are not available for the design of arbitrary shell structures, with the exception of membrane structures.

The proposed computer tool, combined with the parametric design option, promises to fill this void, providing the designer with a simple interactive tool that finds the optimal shape of structural elements for timber shell structures. The parametric design option is provided by CustomObjects, a Microstation sub program by Bentley. Automating this traditionally timeconsuming development process will result in considerably reduced design costs.

• INTRODUCTION

• TIMBER RIB SHELLS

• THE PLANK LINE

• PARAMETRIC DESIGN

• RESULTS

• SUMMARY

• REFERENCES