EXPERIMENTAL STUDY ON THE AXIAL COMPRESSION OF THIN-WALLED STEEL TUBE/BAMBOO-PLYWOOD COMPOSITE HOLLOW COLUMNS

To study the axial compression performance of thin-walled steel tube/bamboo-plywood composite hollow columns, three group tests of axial compression specimens were carried out to investigate the failure characteristics, bearing capacity and deformation of the composite columns. The influence of slenderness ratio, net sectional size, hollow ratio, sectional mode, row number and relative vertical spacing ratio of binding bars on the axial compression performance were analyzed. The results indicated that the failure modes can be divided into debonding glue failure at the end or middle of the column, crush failure of bamboo plywood at the end of the column, broken damage at the end of the column or between the binding bars, and the compressive buckling failure. The increase in the slenderness ratio enlarges the risk of buckling failure, and the increase in the net sectional size is the key factor to improve the ultimate bearing capacity. Sectional assembly can affect the failure modes of the composite column. Setting binding bars can improve the compressive stability of the composite column, and optimizing the design of the row number and relative vertical spacing ratio of binding bars can improve the contact effect of each material interface to increase the bearing capacity. A calculation method of the bearing capacity was formulated through the nonlinear regression analysis.