Creep Properties and Life Prediction of Bamboo Scrimber Subjected to Long-Term Compression

Abstract

The compressive creep performance of bamboo scrimber is an important index to be considered in the column component design. This study investigates the creep failure mode, creep strain, and creep compliance of long-term compression of bamboo scrimber under indoor environment and proposes a load grading life prediction methodology for compressive creep. The approach involves establishing a three-branch Kelvin–Voigt (KV) model for creep compliance and a four-branch generalized Maxwell model for shear relaxation. Based on these constitutive models, a finite element model is developed to simulate the creep behavior of bamboo scrimber under compression. The creep life of bamboo scrimber in parallel-to-grain is predicted using the finite element-derived creep strain data in combination with a creep failure criterion. The results demonstrate that failure mode of bamboo scrimber under compressive creep is characterized by lateral bending deformation and instability. The compressive creep compliance is load-level dependent, showing a nonlinear viscoelastic behavior where higher load levels lead to an accelerated increase in compressive creep compliance. The fitting coefficients of the three-branch KV model of creep compliance for the two loads were 0.989 and 0.991, while the four-branch generalized Maxwell model for shear relaxation yielded a perfect fit with coefficients of 1.00, indicating high fitting accuracy. Based on the model predictions, the creep life of bamboo scrimber under compression in parallel-to-grain at 20%–40% load levels ranges from 50 years to 313 days. These results suggest that bamboo scrimber exhibits considerable creep deformation magnitude under sustained long compressive loading, which may fail to meet the requirements specified in ASTM D6815-22a. The findings of the paper provide theoretical support for the creep design of bamboo scrimber column.