Development of Preliminary Curved Bamboo Member Design Guidelines through Finite Element Analysis

Abstract

Bamboo is emerging as a lightweight, versatile and renewable material that is projected to realise new methods of construction. There is a growing demand for using bamboo in different regions across the world. However, there are no specific design standards or guidelines that capitalise on the unique circular hollow cross section and internal nodal support of bamboo. Furthermore, there has been no strict analysis into how the curvature of bamboo members can help to better distribute stress through a structure. Bamboo is known as a more environmentally sustainable material than standard timber; however, due to the naturally occurring diaphragm nodal structure, it is less orthotropic in mechanical behaviour, with more out of plane stiffness than timber. To address this issue, this paper presents finite element analysis of three varying bamboo structures, each featuring a varying member curvature and lateral support system. In this paper, a preliminary set of design guidelines have been proposed for bamboo members, maximising the performance of its inherent mechanical properties. These guidelines propose the use of thick, low diameter bamboo members in axial loading and thin, high diameter members in flexural situations. Where available, the preliminary guidelines introduce the importance of curved bamboo members to uniformly distribute forces and crossing arched members to eliminate the need for lateral support systems, thereby reducing the total material required for construction. Finally, this report presents some novel consideration of the out-of-plane buckling of curved bamboo members–although for this purpose it does not consider the effect of the diaphragm components of bamboo, a source of future research and more comprehensive design guidelines.

BambuFlex – a Digital Form-Finding Tool for Curved Bamboo Structure based on Indonesian Bamboo

“…The culm diameter also has varying diameters, wall thickness, and internode length (Lorenzo et al, 2020). Several approaches exist, such as using mean value (Seixas et al, 2021), lowest value (Crolla, 2017), or disregarding the variability concerning other structural members (Tahmasebinia et al, 2020).…”