Experimental investigation on the dowel-bearing properties of neosinocalamus affinis-based bamboo scrimber

The experiments on the dowel-bearing of neosinocalamus affinis-based bamboo scrimber (NABS), considering the angles between load and fiber direction (LFD) and the dowel diameters, were carried out to investigate the dowel-bearing properties, including its failure modes, dowel-bearing strength, and embedded initial stiffness. Referring to the standard ASTM D5764, a controlled displacement was employed to load till specimen failure during the experiments. Then, the load-displacement curves of all specimens were obtained, and the dowel-bearing strength of NABS was calculated based on the load-displacement curve according to the 5 % bolt diameter offset method, and the embedded initial stiffness was derived from the slope of the elastic region of the load-displacement curve. Through a sorting-out and analysis of the experimental results, the types of damage modes of the specimens transit from brittle failure to plastic failure with the LFD angles increases from 0° to 90°, which is mainly dominated by adhesive layer damage; The dowel-bearing strength of NABS at each LFD angle exhibits stability, the coefficient of variation is between 2.4 % and 10.2 %, and its average for each group was calculated, respectively, which decreases with the increase of bolt diameter; Similar to the dowel-bearing strength, the coefficient of variation of embedded initial stiffness is between 2.2 % and 9.2 %, and its average for each group was also computed individually, which increases with the increase of bolt diameter and decreases with the LFD angles increases from 0° to 90°. Finally, the empirical equations for predicting the dowel-bearing strength of NABS were developed by regression analysis of the experimental data and Hankinson formula, and the equation to predict the embedded initial stiffness under different LFD angles was discussed. The results can benefit to depth understanding of the dowel-type connection and structural design of bamboo scrimber.