中国古建筑简化分析研究

Simplified analytical reresearch on ancient Chinese timber structures

为研究中国古建筑的固有特性和抗震性能,根据西安城南门箭楼复原工程资料,采用半刚性弹簧单元来模拟实体结构的榫卯、斗栱和柱础连接,建立箭楼大木作构架的局部和整体两种有限元模型。采用Block Lanczos方法,分别进行模态分析,得出模型的前10阶频率和振型;采用瞬态分析方法,在El Centro波、Taft波和兰州人工波三种地震激励下分别进行时程分析,得到模型的位移和加速度时程曲线。通过比较两种模型的基本参数和频率、振型以及地震激励响应三者的相对误差,探讨采用局部模型代替整体模型进行其结构抗震性能分析的可行性。分析结果表明,中国木结构古建筑可用局部模型近似代替整体模型进行动力特性简化分析。文中提供的方法和结论,可为古建筑维护和复建工程提供一定的借鉴。

In order to study the inherent characteristics and the seismic characteristics of Chinese ancient buildings,according to the rehabilitation engineering data of embrasured watchtower of southgate of Xi＇an City,two finite element models of local and global of large wooden frame of embrasured watchtower are obtained by applying semi-rigid spring element to simulate the joint of mortise-tenon,dou-gong and column-foundation in the real wooden structure.The first 10 inherent frequencies and vibrations of models are obtained by analysing the finite element model,using the method of Block Lanczos with full transient analysis,considering two models subjected to El Centro ground motion,Taft ground motion and Lanzhou artificial ground motion excitation,got the model displacement and acceleration time history curves.Comparing the two model＇s basic parameters and the relative errors of frequencies,vibrations and the excitation effects under the three ground motions to discuss the feasibility of analysis of seismic performance using the local model instead of the whole model,drew the conclusions that the local model can be used instead of the overall model of Chinese ancient buildings for dynamic characteristics analysis and research.Based on the results,the analysis method and conclusions could be referenced to other ancient strueture protection and rehabilitation.