中国古建筑动力特性及地震反应

Vibration Characters and Seismic Response of Chinese Ancient Buildings

以故宫英华殿为例,引入了反应中国古代木结构榫卯连接的半刚性单元,并将斗简化为三向减震弹簧,建立了有限元模型.通过动力分析,得到了英华殿的前10阶自振周期及振型;通过输入三向天津波进行地震时程响应分析,得到了英华殿跨中部位屋顶节点、柱顶节点及柱根单元的地震响应曲线,并对比分析了榫卯连接、斗及侧脚等构造对地震反应的影响.研究表明:英华殿的基频较低,在x向振动以第一振型为主,在y向振动以第二振型为主,在地震作用下屋顶的加速度响应要小于柱顶,榫卯连接、斗及侧脚等构造措施均有利于减小结构的地震响应.

Ying-hua Palace in the Forbidden City is taken as an example. FEM of Chinese ancient wood structure is built on the basement of hypothesizes that tenon-mortise joints are considered as semi-rigid elements and tou-kungs are considered as 3-dimensional springs. By modal analysis the first 10 periods as well as vibration modes are obtained. Then Tianjin seismic waves in 3 dimensions are input and response curves of typical nodes as well as elements are studied. Aseismic characters of constitutions such as tenon-mortise joints,tou-kung and ce-jiao are discussed. Results indicate that base frequency of Ying-hua Palace is low, whose main mode in x direction foreuses on No 1 and No 2 on y direction ; Under seismic forces responses of roof are weaker that those of top of columns; Constitutions of tenon-mortise joints, tou-kung and ce-jiao are helpful for seismic resistance of ancient structure.