竹集成材钉连接顺纹向的抗剪性能

Shear behavior of laminated bamboo lumber nailed joint loaded parallel to grain

为研究竹集成材(LBL)钉节点顺纹向受力时的承载性能、变形特性和破坏机理,对125个钉节点双面剪切试件进行了单调静力加载破坏性试验,研究参数包括钉直径、列数和行数.试件的破坏主要有钉帽下部的竹材局部压屈、销槽承压破坏、双铰破坏及LBL劈裂破坏.钉节点的抗剪承载力随钉子直径、列数和排数的增加而增大,但群钉节点的承载力明显小于单钉节点的承载力之和.提出并验证了群钉节点的有效钉子数量和销槽承压有效长度系数计算公式,对比分析了4种常见的屈服点确定方法,结果表明5%钉直径偏移法更适合预测LBL钉节点的屈服荷载.

To study the load carrying capacity, deformation behavior and failure mechanism of the laminated bamboo lumber(LBL) nailed joint loaded parallel to grain,125 specimens with double shear plane were tested to failure under monotonic loading.The influence parameters investigated include nail diameter, number of lines and rows of nails. Results show that four typical failure modes are investigated including nail pulling through the side members,embedment,and hinges formed in side and middle members,and splitting.The load carrying capacity of the LBL nailed joint is obviously less than the sum of capacity of the single nail. Furthermore, effective number of nails in multi-nail joint and dowel-bearing length coefficient was proposed and verified.Four commonly used methods to determine the yield point of nailed joint were compared, and it is found that the 5% of the nail diameter method is more suitable to evaluate the yield load of the LBL nailed joint.