Behavior and strength of rectangular bamboo scrimber columns with shape and slenderness effects

Abstract

To investigate the mechanical properties of bamboo scrimber columns under axial compression, sixty specimens with different slenderness ratios and cross-section shapes, including a square cross-section and rectangular cross-section, were studied. The slenderness ratio λ of the columns ranged from 5.20–83.14, and the aspect ratio of the cross-section h/b ranged from 1.0–2.0. The results show that the failure modes of the bamboo scrimber columns include strength failure and instability failure. Columns with a rectangular section are more prone to instability failure for the same slenderness ratio, and the instability failure always bended along the long side of rectangular columns. The columns with a large slenderness ratio develop rapidly and have a small stiffness in the early stage due to the lateral bending deformation. Under the same level of load, bamboo columns with a larger slenderness ratio have a larger lateral displacement. For long columns, the axial strain cannot reach the ultimate strain of the bamboo, and the material strength cannot reach full development due to the instability failure of the columns. A new model to calculate the stability coefficient is proposed, considering multiple factors. In this model, in addition to the variable slenderness ratio λ, the aspect ratio of the cross-section h/b, is introduced as a new variable. The model exhibits a good applicability for both square and rectangular cross-sections.