Effect of orientation and arrangement of bamboo strips on structural strength of laminated bamboo beam

Abstract

This study evaluates the effect of orientation and arrangement of bamboo strips on structural strength of laminated bamboo beams, the study is motivated by the anatomical features of bamboo internode and earlier studies that has shown that strength properties increase from inner to outer layer of the culm and so is the concentration of the cellulose fibers. Mature Bamboo was harvested, split, treated and dried for the study; tensile test was carried out on strips with nodes, strips with outer skin removed and strips with outer skin intact. Laminated bamboo beams were made in various variations; two orientations, strips facing each other and strips facing same direction in respect to inner and outer face of culm, beams with coinciding nodes at mi point and beams made with jointed strips. Bending and compression tests were performed on the specimens. The results showed that orientation of bamboo beams and direction of loading has an effect on flexural strength of laminated bamboo beams, beams loaded on the edge had the highest flexural strength than beams loaded on the face, beams with strips facing the same direction and loaded on the inner face had the highest Modulus of Elasticity for the face loaded beams, nodes had a reducing effect on longitudinal tensile strength but had reinforced effect increasing flexural strength of beams while loaded on the face and on the edges, although having staggered joints in strips reduced the flexural strength of beams, the achieved values were sufficient for common construction works compared to commonly used timber species.