穿斗式木结构中节点的抗弯性能试验研究

Experimental study on the moment-resisting performance of interior joints with wooden peg

以西南传统民居穿斗式木结构穿销中节点为研究对象,设计制作了2个足尺横向中节点和2个足尺纵向中节点模型试件,分别对两类节点进行单调加载和低周往复加载试验,得到两类节点的破坏模式、抗弯承载力、抗弯刚度、延性和耗能能力。结果表明:横向中节点主要在榫卯挤压区域发生嵌压塑性变形以及在木销受荷区域发生弯剪变形,纵向中节点易在榫颈位置发生折断破坏;横向中节点的初始刚度较纵向中节点高,横向中节点的抗弯承载力可达纵向中节点的2倍;横向中节点和纵向中节点的滞回曲线均表现出明显的捏拢和滑移现象,横向中节点的耗能能力较强;穿斗式木结构横向中节点和纵向中节点都具有良好的变形能力,横向中节点表现出较好的延性,但纵向中节点的延性很低;纵向中节点是穿斗式木结构中的薄弱节点,需要在穿斗式木结构的安全维护中重点关注。

In order to study the moment-resisting performance and seismic behavior of the interior joints with wooden peg of Chuan-Dou type wooden frame,two full-scale interior beam-column joint specimens of transverse frame and two that of longitudinal frame were designed and fabricated.Monotonic loading and low cyclic loading tests were carried out on the two types of joints,respectively.The failure mode,moment-resisting capacity,flexural stiffness,ductility and energy dissipation of the two types of joints were obtained.The results showed that the failure mode of transverse interior joint was the embedment plastic deformation on the mortise and tenon contacting area as well as the bending-shear combined deformation of wooden peg,while longitudinal interior joint was broken off at the neck of tenon.The initial stiffness of the transverse interior joint was higher than that of the longitudinal interior joint.The moment-resisting capacity of transverse interior joint could reach two times of that of longitudinal interior joint.The hysteretic loops of the two types of joint exhibited obvious squeezing and slip.The energy dissipation of the transverse interior joint was higher than that of the longitudinal interior joint.Both the two types of joint exhibited good deformation capacity,the transverse interior joint exhibited good ductility,while the longitudinal interior joint exhibited poor ductility.The longitudinal interior joint in the frame is the weakest part and need to be noted on the safety maintenance of the Chuan-Dou type wooden frame structure.