Experimental study and analysis of the bond-anchorage properties of laminated flattened-bamboo lumber connections with glued-in steel rod

To improve the utilization rate of raw bamboo and reduce the amount of adhesive, this paper studied a new type of laminated bamboo lumber, that is, laminated flattened bamboo lumber. The monotonic pull-out tests were carried out on 56 specimens with glued-in steel rods of three different diameters (12 mm, 16 mm, and 20 mm, respectively; the thickness of the adhesive layer was 3 mm) of laminated flattened bamboo lumber, and the effect of anchorage length and diameter of the steel bar on the mechanical properties of bond anchorage were studied. In addition, the specimens with a diameter of 12 mm and an anchorage length of 100 mm were selected to study the effect of different thicknesses of the adhesive layer (between 2 mm and 4 mm) on the mechanical properties of bonded anchorage. The results showed that the failure modes could be divided into three types. For the specimens with the same anchorage length, the larger the diameter of the glued-in steel bar was, the larger the ultimate pullout load would be; when the diameter of the steel bar was the same, the ultimate pullout load of the specimens increased with the increase of the anchorage length. When the diameter of the glued-in steel bar was 12 mm, the average bond strength decreased with the increase in slenderness ratio. When the diameter of the glued-in steel bar was 16 mm and 20 mm, the average bond strength first increased and then decreased with the increase of the slenderness ratio, and the turning slenderness ratio points were 8.75 and 5, respectively. The ANOVA analysis with parameters revealed that the rebar’s diameter and length significantly impacted the bond-anchorage characteristics of the glued-in rod connection in laminated flattened bamboo lumber.