广府古建筑木结构箍头榫节点抗震性能研究

为研究广府古建筑木结构中广泛采用的箍头榫节点的抗震性能,以梁截面高度、柱直径、梁榫宽和柱顶轴压力为研究参数,设计制作了8个缩尺节点试件进行低周反复荷载试验,得到了不同研究参数下箍头榫节点试件的破坏形态、滞回曲线、骨架曲线、延性、承载力退化、刚度退化及能量耗散能力等。研究表明:各箍头榫节点试件转角达到0.1rad时,仍可维持稳定的承载状态,其承载力退化不明显,具有较好的承载性能以及良好的延性。试件的破坏形态包括柱内侧梁榫顶部(或底部)顺纹拉裂破坏、柱外侧梁榫竖向劈裂破坏和水平劈裂破坏;各节点的弯矩-转角滞回曲线均呈反Z形,且有明显的"捏缩"现象;在试验设计参数范围内,节点的转动刚度、极限弯矩和耗能能力均随着梁截面高度和柱直径的增大而增大,并随着梁榫宽的增大呈现出先增大后减小的趋势,一定范围内改变柱顶轴压力对试件抗震性能影响不大。采用有限元软件ABAQUS建立了箍头榫节点模型,并与试验进行了对比验证,结果表明该模型可较好地模拟反复荷载作用下的节点滞回性能。通过参数分析进一步研究了不同参数下箍头榫节点的弯矩-转角曲线,结果表明节点的屈服弯矩和极限弯矩基本与梁截面高度、柱直径大小呈线性正相关关系。

Seismic behavior of hoop head tenon-mortise joint in ancient wood structures in Guangfu

In order to investigate the seismic behavior of hoop head tenon-mortise joints which were widely used in ancient wood structures in Guangfu, eight reduced scale joint specimens were made with different test parameters, including beam height, column diameter, tenon width and axis pressure of column. Cyclic loading tests on these specimens were carried out, and the failure patterns, hysteresis loops, skeleton curves, ductility, strength degradation, stiffness degradation and energy dissipation capacity of the hoop head tenon-mortise joint specimens with different test parameters were studied. It is shown that when the joint rotation reaches 0.1 rad, the joints have stable load resistance, and strength degradation is not obvious, indicating that the joints have satisfactory bearing capacity and ductility. Their failure patterns include parallel-to-grain cracking of the top (or bottom) of beam tenon, as well as vertical or horizontal fracturing of beam tenon. The moment-rotation hysteresis loops of the joints show a reverse Z shape and obvious pinching. For the considered joint specimens, rotational stiffness, ultimate bending moment and energy dissipation capacity increase with the increase of beam height and column diameter, and they increase and then decrease with the increase of tenon width. Axis pressure of column has little effect on seismic behavior of the specimens. A finite element model was developed by using ABAQUS software to simulate the performance of the hoop head tenon-mortise joints, and it was validated through comparing with the experimental results. It is shown that the model can simulate the hysteretic behavior of the joints under repeated loading well. The influences of different parameters on the moment-rotation curve of the joints were further studied via parametric analyses. The results show that the yield moment and ultimate moment of the joints have a linear positive correlation with beam height and column diameter.