传统木结构柱脚节点力学模型及有限元模型研究

Study on mechanical model and finite element model of column base joint in traditional timber structure

木柱直接立于柱础石上是传统木结构中柱脚节点最常见的连接样式。在水平反复荷载作用下,由于木柱与础石之间一般不存在任何的连接,木柱会以柱脚与柱础石相接触的边缘点为转动支点发生转动,进而产生摇摆,其在摇摆状态下的受力性能对整个结构的稳定发挥了积极的作用。为研究传统木结构柱脚节点在地震作用下的转动性能,以浮搁柱础连接为研究对象,首先分析了木柱在水平反复荷载作用下的受力机理,建立了柱脚节点理论计算公式;随后依据柱脚滞回曲线的特点,提出了含有柱脚弹簧单元的木柱杆系有限元分析模型。结果表明:柱脚节点力学模型的计算结果与试验曲线吻合良好;木柱杆系有限元分析模型有效地反映了木柱在摇摆状态下的滞回特点。

Timber column is directly placed on the stone base in traditional timber structure,which is the most common form of column base joints.Timber column can rotate around the edge of column foot in contact with stone base under horizontal cyclic loads due to no connections between the timber column and the stone base,which produce the swing.The mechanical behavior of the timber column in the rocking state plays an active role in the stability of the whole structure.The foundation column directly above was selected to study the rotation performance of column base joint in traditional timber structure under earthquakes.Firstly,based on the analysis of the force mechanism of the timber column under horizontal cyclic loads,the theoretical calculation formula of column foot joint was established.Subsequently,according to the characteristics of its hysteretic curve of column foot,beam-spring finite element model,including spring element on column base joint,was established.The results show that the calculated results from the proposed model of column base joint were in good agreement with experimental results.The beam-spring finite element model effectively reflects the hysteretic characteristics of the timber column in the swaying state.