竹胶板双剪螺钉连接的承载性能试验研究

Experimental investigation on behavior of lumber-plybamboo-lumber double-shear screwed connections

为探究竹胶板和自攻螺钉在夹板剪力墙中的使用效果,对10组竹胶板双剪螺钉连接试件和4组定向刨花板(OSB)双剪螺钉连接对比试件进行单调加载试验.结果表明:在保证不小于22mm板端距情况下,竹胶板双剪螺钉连接能较好地避免板边撕裂破坏,并充分发挥自攻螺钉的高抗弯和抗拔性能;横纹加载的竹胶板双剪螺钉连接在极限承载力上比顺纹加载时高15.5%~19.8%,但在初始刚度、延性系数上均与顺纹加载时相差不大;竹胶板双剪螺钉连接的极限承载力比以木基结构板材为中心夹板的双剪钉连接高64%~146%,故以竹胶板和自攻螺钉分别作为中心夹板和钉连接件有助于快速提升夹板剪力墙的抗侧力性能.依据我国《木结构设计标准》GB50005—2017算得的双剪螺钉连接极限承载力偏低,但所预测的屈服模式有较好的准确性.

To investigate the feasibility of using plybamboo panels and self-tapping screws in midply shear walls,monotonic tests were conducted on ten groups of lumber-plybamboo-lumber double-shear screwed(LPLDSS) connections,as well as four groups with oriented strand board(OSB) sheathing for comparison.Results show that when the edge-distance is no less than 22 mm,LPLDSS connections can avoid sheathing edge-tear failure and take full use of the high bending and withdrawal capacity of the self-tapping screws.LPLDSS connection loaded perpendicular to the grain of lumber has a 15.5%~19.8% higher ultimate strength than that loaded parallel to the grain,whereas both their initial stiffness and ductile factors are quite close.Compared to the double-shear nail connections with common wood-based sheathing,LPLDSS connections show higher ultimate strength by 64%~146%,indicating the great potential of plybamboo panels and self-tapping screws in improving the lateral performance of midply shear walls.The GB50005—2017 design code will underestimate the ultimate strength of the double-shear screwed connections,but can generally predict their failure modes.