Strength Characteristics of Bamboo Culm II.

Abstract

Strength tests of madake (Phyllostachys reticulate) and mosochiku (Phyllostachys pubescens) culms, which are useful bamboos in Japan, were conducted in the green condition. Internal diameter d was estimated from external diameter D in the culm by the known regression line d＝0.81D. Section properties in the culm were calculated from D and d. Strength properties of the culm were calculated from the assumptions that the culm was homogeneous and a hollow circular cross-section material. As a result of tests, the strength properties of the culm could be expressed by several regression lines with external diameter D as explanatory variable. Of these, regression lines of stiffness data (flexural rigidity E・I, axial rigidity E・A, torsional rigidity G・J) necessary for structural analysis of space frame are as follows, regardless of bamboo species.Log E・I＝3.