Experimental study on bond performance of the single glued-in rod in inorganic-bonded bamboo composite parallel to the grain

In contemporary bamboo and timber structures, the glued-in rod (GiR) has become an efficient method to improve the performance and reliability of connections. To investigate the bond performance of a single GiR in inorganic-bonded bamboo composite (InorgBam) parallel to the grain, pull-out tests were conducted on 72 specimens with varying diameters, strength grades, and anchorage lengths of the threaded rod. Three typical failure modes were observed: shear failure, shear accompanied by splitting failure and rod yield failure. The experimental results revealed a notable transition from shear failure (brittle) to yield failure (ductile) as the anchorage length increased. The critical anchorage lengths for various diameters and strength grades were recommended in this study. A relationship between average bond stress and anchorage slenderness ratio was also established. Based on typical models for GiR in timber, an analytical formula was developed to evaluate the load-carrying capacity of specimens considering different failure modes. The predicted results agreed with the experimental data, confirming the reliability of the proposed theoretical formula. It can offer valuable insights for enhancing the design and performance of GiR in InorgBam materials.