地震作用下重力坝非线性振型响应的耦合性分析

以结构初始弹性振型为基向量,将地震荷载向量展开为振型荷载的组合。以Koyna重力坝为例,采用混凝土损伤塑性模型和非线性时程分析法,计算各振型荷载引起的大坝非线性响应。取地震加速度峰值为0.5g,给出了Koyna、El Centro实测地震波和1种人工地震波作用下大坝前5阶振型荷载引起的坝顶位移响应。结果表明,非线性情况下,坝顶位移响应依然由与荷载分布相同的振型分量主导,重力坝振型响应具有弱耦合性。

Modal coupling analysis of nonlinear seismic response of gravity dams

The effective seismic load is expanded into the initial elastic modal vector of the structure as a combination of modal loads. Taking the Koyna dam as an example, a plastic damage concrete model and nonlinear time-history analysis method are used to calculate the nonlinear response of the dam caused by various modal loads. Subjected to the Koyna, El Centro and artificial ground motion with apeak value of earthquake acceleration 0. 5g respectively, the displacement responses of dam crest caused by the first 5 modal loads are provided. The results show that the nonlinear displacement response is still dominant by the same mode as modal load, and the weak coupling of modal response can be ignored for the calculation of nonlinear seismic response of gravity dams.