Flexural creep behavior of hierarchical bamboo structure using time-temperature-stress superposition principle

The long-term flexural creep properties of graded hierarchical bamboo are important to structural design in civil construction. The present study conducted the short-term flexural creep tests at a series of temperature (30–170 °C) and stress (7–15 MPa) conditions, for the bamboo from both inner and outer parts. The application of time-temperature superposition principle (TTSP) and time-temperature-stress superposition principle (TTSSP) was analyzed for the creep behavior of bamboo with regard to hierarchical structure. The results confirmed the feasibility of TTSP and TTSSP in flexural creep of bamboo by horizontal shifting. A creep model based on Findley power law was successfully employed to predict the flexural creep response of bamboo. Additionally, the sample from inner part of bamboo displayed a more pronounced flexible creep response compared with the sample from outer part, attributing a low fiber volume fraction in inner part due to bamboo growth strategy. The findings in this study broaden the knowledge of bamboo rheology, and is helpful for further work on the bamboo growth strategy effect on mechanical properties.