Experimental study of partially encased bamboo scrimber columns under axial compression

Both bamboo scrimber and section steel are extensively employed in the construction industry however bamboo scrimber as a large composite member, easily experiences buckling and splitting under compression. To solve the problem of insufficient bearing capacity, a partially encased bamboo scrimber (PEBS) column was developed in this paper, and the PEBS column consisted of an H-shaped steel member with two rectangular bamboo scrimber members placed inside the web and flanges, forming a partial buckling restraint configuration. The aim of this arrangement was to enhance the axial compressive performance of the bamboo scrimber members through partial lateral confinement. To investigate the influences of the composite effect and specimen size, a total of 45 specimens were tested under axial compression to analyse the failure modes, load–displacement relationships, and mechanical properties. The results revealed that the composite specimens ultimately failed owing to buckling and wedged splitting in the bamboo scrimber members. The partial buckling restraint exhibited a substantial improvement in axial bearing capacity through delaying the buckling of the H-shaped steel and failure of the inner bamboo scrimber, leading to a further enhancement in the safety stock. Finally, a calculation method was proposed to predict the ultimate bearing capacity of the PEBS column.