多层古建筑木结构柱脚节点力学性能研究

MECHANICAL PROPERTIES OF COLUMN FOOT JOINTS IN MULTI-STOREY TRADITIONAL CHINESE TIMBER STRUCTURES

  • 摘要: 开展了多层古建筑木结构柱脚节点试验研究,揭示了不同楼层柱脚节点的变形机理并评估了其力学性能,基于受力机理和刚体摆动特性建立了多层古建筑木结构柱脚节点简化力学模型。研究表明:上部楼层柱脚节点以木枋横纹嵌入变形为主且变形显著,底层柱脚节点以木柱顺纹受压变形为主但变形较小。随着竖向荷载的增加,柱脚节点弯矩承载力增加,但上部楼层柱脚节点弯矩-转角滞回曲线捏拢现象明显,强度退化因子在0.8~0.9;底层柱脚节点弯矩-转角滞回环高度重叠,强度退化因子大于0.95。上部楼层柱脚节点耗能能力随竖向荷载的增加而增加,处于较低竖向应力状态的柱脚节点耗能增幅较为显著。简化力学模型与试验曲线吻合良好,可用于多层古建筑木结构性能分析。

     

    Abstract: An experimental study is presented on the column foot joints in multi-storey traditional Chinese timber structures, the joints' deformation mechanisms and mechanical properties were investigated and evaluated, respectively. A simplified analytical model was further established upon the load-bearing mechanisms of the column foot joints and the characteristics of rocking rigid body. The research indicated that: the upper floor column foot joint is mainly wood grain embedded deformation and the deformation is significant, while the bottom column foot joint is mainly wood column parallel grain compression deformation, but the deformation is small. With the increase of vertical compression loading, the moment-resisting capacity of the column foot joints increased. However, the hysteresis curves of the column foot joints in upper stories exhibited serious pinching effect, the strength degradation coefficients were between 0.8 to 0.9; the hysteresis loops of the column foot joints in ground storey overlapped each other, and the strength degradation coefficients were greater than 0.95. The energy dissipation capacities of the joints in upper stories increased with the increase of the vertical compression load, and the increase amplitude of the joints with low vertical stress was more significant. The simplified model agreed well with experimental curves and could be utilized in the structural analysis of multi-storey traditional Chinese timber structures.

     

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