Experimental investigations on the load-bearing properties of dowel connection joints of bamboo scrimber

The joints in bamboo structures are critical, and dowel connections are the most convenient form of joint. Research on dowel-bearing behaviour is important to develop the theory of joints for bamboo structures. One hundred fifteen half-hole dowel-compression specimens were tested in this study to explore the effects of specimen length, dowel diameter and fibre direction on the dowel-bearing behaviour of bamboo scrimber. Re-sults showed that length had little effect on the stiffness and dowel-bearing strength of bamboo scrimber. When the dowel diameter increased from 8 to 20 mm, the stiffnesses of parallel to grain and perpendicular to grain specimens both increased by more than 43%, while the dowel-bearing strength of parallel to grain specimens decreased linearly from 177.11 MPa to 126.74 MPa, and the variation law of the perpendicular to grain speci-mens conformed to the trend of the quadratic function. When the angle between the direction of the bamboo fibre and the horizontal direction changed from 90 degrees to 0 degrees, the stiffness decreased from 63.55 kN/mm to 32.62 kN/mm, and the dowel-bearing strength decreased from 167.22 MPa to 138.43 MPa and exhibited different downwards trends with 45 degrees as a boundary. Based on the calculation concept in Code for the design of timber structures in China, the calculation formula of dowel-bearing strength of bamboo scrimber was proposed by considering the influence of dowel diameter and fibre direction. The predicted results are in good agreement with the test results, which have good applicability to bamboo scrimber and can effectively provide a design method for dowel connection joints of bamboo structures.