Flexural creep behavior of bamboo culm (Phyllostachys pubescens) in its radial direction

As a construction material, the phenomenon of creep is critical to bamboo structural design. The present work investigates variation of flexural creep behavior of bamboo (Phyllostachys pubescens) in its radial direction. Bamboo specimens were divided into two groups, half of the specimens were loaded by the green side, which fiber-rich outer culm wall was in compression (A); the other half were loaded by the yellow side, which fiber-rich outer culm wall was in tension (B). The specimen in both groups were cut into three sections along radial direction, the outer part (A1, B1), the middle part (A2, B2), and the inner part (A3, B3). All specimens were conducted to a 24 h-creep tests. The results show that: The creep resistance of outer part of bamboo is favorable, no matter which kind of loading way. Compared to type A loading with fiber-rich part, specimens of type B loading with fiber-less part showed a higher creep residual strength. The fiber volume fraction was linearly associated with the initial creep of type A and the final creep of type B. It mainly related to the feature and distribution of fiber and parenchyma.