Study on the Mechanical Behavior of the Bamboo Scrimber Dowel-Bearing Under Sustained Loading Based on SICD Method

The mechanical behavior of bamboo scrimber dowel-bearing under sustained loading was investigated via the Stepped Isothermal Creep Deformation (SICD) method using a 30-ton multi-field coupling system, with the test conducted over a duration of 51.5 h. Experimental results revealed three typical failure modes: material failure, local compression failure, and crushing failure. The damage degree increased linearly with stress level. SEM microstructural analysis further indicated that failure originated from progressive fracture and bending of fiber bundles, as well as layer compression and cracking induced by mechanical loading. The deformation process of bamboo scrimber dowel-bearing under sustained loading comprises four distinct stages, namely short-term deformation, initial creep, stable creep, and divergent creep. The divergent creep stage manifests exclusively at stress levels of SL = 0.6, while at lower-stress levels, SL = 0.2 and SL = 0.4, only the first three stages are observed within the 51.5 h test duration. In addition, a preliminary analysis was conducted on the stiffness and strength reduction in bamboo scrimber dowel-bearing under sustained loading. These research findings elucidate the mechanical behavior of bamboo scrimber dowel-bearing under sustained loading, providing preliminary insights to inform future durability assessment and design methodology development for bamboo scrimber joint connections.