DEVELOPMENT OF A METHOD TO TEST BAMBOO CULMS IN DIRECT TORSION

The development of a method for testing whole bamboo culms under direct torsion is described. The overall approach is an adaptation of the direct test for timber as describe in the ASTM D198-15 standard, which implements a universal testing machine to convert applied load into torque over a specimen. To realize such a torsion test requires developing a gripping fixture to induce torsion over bamboo specimens, which is a challenge, due to the naturally round nature of the bamboo culm. Several approaches are considered, including the use of cement/epoxy, wrapped cables, or bolted connections. An evaluation of each methodology was proposed to assess criteria such as slippage, failure mechanism, feasibility, assembly stability, repeatability, and safety. This study concludes that the use of non-shrink cement, to bond the culm to an exterior steel sleeve, is preferable, and provided an overall description of the testing regime proposed