Influence of slenderness ratio and sectional geometry on the axial compression behavior of original bamboo columns

Bamboo has been widely used as a load-bearing material in construction; however, there are limited studies on the stability of slender original bamboo columns. Based on the experimental investigation of thirty-nine original bamboo columns, parametric analyses were conducted to investigate the influence of the diameter–thickness ratio, cross-sectional area and slenderness ratio on the axial compression behavior of original bamboo columns. The test results indicate that the failure modes of the columns are substantially affected by the slenderness ratio and diameter–thickness ratio. For columns with the same diameter–thickness ratio, the ultimate bearing capacity was negatively correlated with the slenderness ratio, and the highest reduction rate for the load-bearing capacity caused by the slenderness ratio was 44.39%. Under the same slenderness ratio, when the diameter–thickness ratio increased by 18.75%, the ultimate bearing capacity increased by 82.65%. An excessive slenderness ratio may result in local buckling, leading to underutilization of the material strength when failure occurs and substantially reducing the load capacity of bamboo columns. Local buckling can be mitigated by decreasing the slenderness ratio and increasing the diameter–thickness ratio. According to the test results, the model predicting the compressive bearing capacity of the original bamboo column was proposed considering the slenderness ratio and diameter–thickness ratio, and it was indicated that the proposed model can provide satisfactory predictive results.