Local stability of glued laminated bamboo columns with box sections under axial compression

Laminated bamboo columns with box sections are favored by designers because they overcome the disadvantage of small elastic modulus, but local buckling behavior caused by an excessive width-to-thickness ratio will lead to a non-uniform distribution of stress. The discontinuous cracks at the glued joints and waveform deformation indicate that the local buckling has a significant effect on the bearing capacity of columns with box sections. However, few studies have been reported on the evaluation of bearing capacity considering local stability due to non-uniformity and discontinuity. The experiments on 5 glued laminated bamboo columns with box sections (GLBCs) with different length-to-width ratios under axial compression were carried out. The test results showed that the waveform bulging failure occurred on the surface of GLBCs before the overall buckling, and an obvious debonding failure occurred between the bamboo plates. These failures aggravated the local buckling failure. As the length-to-width ratio increased, the number of waveforms buckling increased, the lower the bearing capacity. To evaluate the local stability of GLBCs accurately, a new anisotropic plate model considering the width correction coefficient and material anisotropy for the critical buckling load of GLBC was proposed. Furthermore, it can be found that an appropriate width-to-thickness ratio can effectively avoid local buckling failure. A formula for the critical width-to-thickness ratio of GLBCs under different slenderness ratios was proposed. In this paper, the anisotropic plate model proposed can accurately evaluate the bearing capacity considering the local stability of GLBCs under axial compression.