新型外包钢板-自攻螺钉连接胶合竹梁柱节点转动性能

Rotational Behavior of Innovative Glued Laminated Bamboo Beam-to-Column Connections Using External Steel Plates and Self-Tapping Screws

摘要:

针对胶合竹材不易预开槽和预开孔以及节点转动时竹材易发生横纹劈裂的问题，研究了新型外包钢板-自攻螺钉连接节点的转动性能。对T形外包钢板-自攻螺钉连接节点和双L形外包钢板-自攻螺钉连接节点共5个试件进行了单调加载试验，分析了节点的破坏模式、初始刚度、极限承载力、变形能力和延性系数。试验发现，T形外包钢板-自攻螺钉连接节点相较双L形外包钢板-自攻螺钉连接节点，各项受力性能参数均较优。布置直径小但数量多的自攻螺钉时，节点（T8×8-M）的破坏表现为钢板和自攻螺钉的受拉断裂以及与胶合竹柱连接的自攻螺钉受拉断裂，布置直径较大但数量少的自攻螺钉时，节点（T6×10-M）的破坏则表现为竹材的横纹劈裂和自攻螺钉的剪切破坏。横纹方向采用自攻螺丝加强，可改善节点的受力性能，对T形外包钢板-自攻螺钉连接节点改善更明显。现行《工程竹结构设计标准》（T/CECS 1101—2022）提供的节点设计方法偏于安全地预测胶合竹自攻螺钉连接梁柱节点的抗弯承载力。

Abstract:

In order to solve the difficulties of slotting and perforating of laminated bamboo， and the problem of bamboo splitting when the beam-to-column connections were rotated， the rotational behavior of innovative laminated bamboo beam-to-column connections using side steel plates and self-tapping screws were studied. Two types of connections were designed， and a monotonic loading test was conducted on 5 specimens， including T-shaped extended end plate connections with side plates that confine the beam and double L-shaped end bracket connection partially confining both the beam and column， to analyze the failure mode， initial stiffness， ultimate bearing capacity， deformation capacity， and ductility coefficient of the connections. The results of the test show that most mechanical parameters of T-connections are better than those of L-connections. The failure of the T-connection using more screws of smaller diameter （T8×8-M） is caused by tensile rupture of steel plates and self-tapping screws， while the failure of the T-connection using less screws of larger diameter （T6×10-M） is caused by bamboo splitting and shear failure of steel plates. The reinforcement of self-tapping screws transversely enhances the mechanical behavior of all connections， especially T-connections. The design code “Standard for design of engineered bamboo structures” （T/CECS 1101—2022） can conservatively predict the bending capacity of the laminate bamboo connections.