Capacity Design and Axial Resistance of Novel Flanged-Plug Bamboo–Timber Composite Members

This paper presents an integrated experimental–analytical framework for a novel bio-based composite member composed of a Moso bamboo culm with an adhesively bonded, flanged timber plug. A capacity-based design methodology produced six ductile configurations in which washer-bearing governs by design. Monotonic axial-tension tests confirmed the intended ductile washer-bearing failure across all configurations. Based on these results, a probabilistic capacity model was established to correct the systematic overestimation of the existing mechanics-based deterministic prediction (approximately 5%–20%) and calibrated to deliver a reliability-consistent safety factor (γcal=1.187), suitable for code-level use. In parallel, a concise interface model was formulated and calibrated (via Bayesian inference) and its slip predictions were validated against DIC measurements. Together, these results provide a compact, design-ready basis for engineering bamboo–timber axial members with predictable, ductile behavior.