Experimental investigation on the bending and bearing performance of bamboo dowels for timber structure connections

This study investigates the potential use of dowels made from thick strip bamboo panel and bamboo scrimber as eco-friendly and cost-effective connectors for timber structures. Mechanical behaviors were analyzed through three-point bending tests and half-hole bearing tests between dowel and spruce–pine–fir (SPF) lumber. The results show that bamboo scrimber dowels significantly outperform thick strip bamboo panel dowels in bending performance, with an average yield strength of 68.29 MPa—higher than that of thick strip bamboo panel dowels (38.56 MPa). Under parallel-to-grain loading, the embedment strength of bamboo scrimber dowels (30.34 MPa) greatly exceeded that of thick strip bamboo panel dowels (10.76 MPa). In contrast, both dowel types exhibited comparable bearing performance under perpendicular-to-grain loading. Digital image correlation (DIC) analysis reveals distinct strain localization patterns and failure mechanisms, consistent with observed damage modes. Current timber design standards tend to overestimate the capacity of bamboo dowel connections, indicating limited applicability. This study provides experimental data and results analysis to support the design and implementation of bamboo dowel connections, thereby advancing the use of bamboo materials into timber engineering.