Tension and compression behaviors of Moso bamboo (Phyllostachys pubescens) for structural use

Moso bamboo exhibits strong mechanical properties and demonstrates high economic efficiency. However, the limited availability of mechanical data and lack of clarity regarding the failure mechanism hinders its application in architecture. In this study, the tension and compression performances of bamboo with various forms and locations were measured to evaluate the stability on the bearing capacity. The interrelationships among the strengths of the samples with various forms were analyzed, along with their respective failure mechanisms, particularly focusing on the node effect by CT scanning. The results showed that the tension strengths increased with height, while they decreased from the outer to inner layer across the wall thickness. The tension strengths at the middle and top of bamboo exceeded those at the bottom by approximately two-fold. At internodes, the tension strength of the outer layer was 3.7 times greater than that of the inner layer, while at nodes it was 15.1 times. The nodes, especially those located at the top and inner layer, were found to be vulnerable to tension forces. The compression strengths parallel to the grain increased from the bottom to the top of the stem, whereas a decreasing pattern was observed in terms of the strength variation perpendicular to the grain. The presence of node reduced the compression bearing capacity in parallel-to-grain, but significantly enhanced compression resistance in perpendicular-to-grain due to a hoop effect in circumferential displacement. Brittle failure was commonly observed in bamboo when they were subjected to tension loading. It exhibited a complete elastic-plastic failure behavior under compression in both parallel- and perpendicular-to-grain. The tension and compression strengths of the samples with different forms exhibited a strong positive correlation. The variations in bearing capacity and failure modes of bamboo were mainly attributed to its structural characteristics, particularly the three-dimensional network structure of nodes. • The variations in tension and compressive strengths of bamboo from various locations were summarized. • The impact of node on the load-bearing capacity was analyzed by considering the biological structure characteristic by means of CT scanning. • The failure modes and damage mechanisms of bamboo under both tension and compression were demonstrated. • The responses of tension and compression strengths among the samples with various forms were established.