传统民居穿斗式木结构栓榫节点抗震性能试验研究

以川西传统民居穿斗式木结构中的栓榫节点为研究对象,参照当地典型工程,制作了4个缩尺比为1∶1.33的榫卯节点,并对其进行低周反复加载试验,得到了栓榫节点的破坏形态、弯矩-转角滞回曲线、骨架曲线、强度和刚度退化规律以及耗能能力等抗震性能指标;利用ABAQUS软件建立有限元模型,分析梁截面高度和栓子截面尺寸对榫卯节点承载力的影响。结果表明:节点的破坏形态主要为半榫节点榫头拔出、采用方形栓子节点榫头发生剪切破坏、采用圆形栓子节点榫头发生折断破坏;柱子基本完好,榫头破坏较为严重;所有节点的弯矩-转角滞回曲线均呈Z形,滞回环的捏拢效应较为明显;采用方形栓子节点的受弯承载力、转动刚度和耗能能力均大于半榫节点,且随着方形栓子截面尺寸的增大而逐渐增大;栓榫试件破坏时节点转角均大于半榫试件,说明栓子的存在能够提高榫卯节点的变形能力;枋截面高度对榫卯节点承载力影响较大,方形栓子边长和圆形栓子直径分别为10~30mm和10~20mm时较为合理。研究结果可为传统民居穿斗式木结构的定量参数化设计和抗震性能分析提供参考。

Experimental study on seismic performance of dowel joints in traditional Chuan-Dou style timber structures

Taking the dowel joints in Western Sichuan traditional Chuan-Dou style timber structures as research focus, four mortise-tenon joint specimens with 1∶1.33 scale were made following the local practice in Western Sichuan. The joint behaviors such as failure modes, hysteretic curves, skeleton curves, strength degradation, stiffness degradation and energy dissipation capacity were obtained through low-cycle reversed loading test. Using ABAQUS software, a finite element model was established to analyze the influence of beam section height and dowel section size on the ultimate bearing capacity of the joints. The results show that the Ban mortise-tenon joint is pulled out, square dowel joints are shear failure and round dowel joint is broken off. The damage to the beam is serious, while there is no damage to the column. The shapes of the hysteretic loops of all the joints are Z-shaped with obvious pinching. The flexural capacity, stiffness and energy dissipation capacity of the square dowel joints are significantly greater than the Ban mortise-tenon joint, and increase gradually as the section size of square dowel increases. The rotational angles of the dowel joints are greater than the Ban mortise-tenon joint, indicating that the dowel joints have superior deformation capacity. The height of the beam section has a great influence on the ultimate bearing capacity of the joints, and diameters of 10-30mm and 10-20mm are suitable for the square dowel and circular dowel, respectively. The results can help guide the seismic performance analysis and parametric design of Chuan-Dou style timber structural dwellings.