Mechanical behavior of cross-laminated timber-bamboo short columns with different layup configurations under axial compression

The axial compressive performance is critical for cross-laminated timber (CLT) when bearing vertical loads. However, the experimental and theoretical research about compressive performance is limited at present. This study employed bamboo scrimber and fast-growing Chinese fir lumber to fabricate cross-laminated timber-bamboo (CLTB) short columns. The influence of layer arrangement (bamboo scrimber and Chinese fir lumber were employed as longitudinal or transverse layer) and structural characteristic of transverse layer (width-thickness ratio and edge gluing) on axial compressive performance was evaluated. Superposition theory was combined to calculate the ultimate bearing capacity based on three assumptions. The results showed that the layer material had a significant impact on the axial compressive strength of CLTB columns. However, the structural characteristics of transverse layer had no significant impact on the compressive performances of CLTB columns. Compared to Chinese fir CLT columns, CLTB columns had higher compressive modulus of elasticity (MOE), compressive strength, ductility and energy absorption. When calculating the ultimate bearing capacity of CLT and CLTB specimens, the compressive bearing capacity of transverse layer using fast-growing Chinese fir can be ignored, but the transverse layer of bamboo scrimber need to be considered. Among the three assumptions, the relative error of ultimate bearing capacity of CLTB specimens calculated by average compressive strength was the largest, the maximum relative error of which was 28%. •CLTB presented better compressive performance than Chinese fir CLT.•Layer materials had a significant impact on the axial compressive strength of CLTB.•The effect of bamboo scrimber can’t be ignored when calculating bearing capacity.•The structural characteristics had no impact on the compressive strength of CLTB.