地震动时间-空间耦合特性对大尺度结构非线性响应的影响机理研究

The effects of spatial variation and the non-stationarity of earthquake ground motion on the structural responses are vital, but the relationships between coupling characteristics of earthquake and the structural responses are hard to be established. The reasons are that the seismic input characteristics can not be controlled quantitatively and that there is a complex nonlinear relationship between the input and the response. In order to solve these problems, the primary goal of this project is to present a comprehensive practical method for simulation the coupling characteristics of earthquake in time and space, and to establish a numerical model describing the coupling characteristics of ground motion with structural characteristics by optimizing the discrete parameters of models. The second destiny of the project is to develop spatial correlation multi-point ground motion fitting method, which can match multiple targets to achieve approximate quantitative control on the input characteristics of the earthquake, and to elucidate the mechanism of ground motion variation on structural response by large-scale nonlinear response analysis for large scale structures. Finally, combined with the approximation technique, a proximate relationship model between earthquake ground motion parameters and structural responses will be established to provide reliable theory basis in selecting input parameters of ground motion and the model considering structure property. The research of this project has great practical significance for the development of the theory of seismic design.

地震动在时间或空间上的变化均会对大尺度结构响应产生重要影响,但其耦合特性与结构响应之间有怎样的联系,至今尚未得到具有普适性的结论。究其原因,一是无法定量控制地震输入特性,二是输入与响应之间存在着复杂的非线性关系。为解决这些问题,本项目首先提出地震动时间-空间耦合特性的表征方法,并通过对离散化模型参数取值的分级优化设计,构建与结构特性相关的地震动时空耦合特性数值模型;其次,提出多目标空间相关多点地震动拟合方法,实现对地震输入特性的近似定量控制,并通过对大尺度结构进行大规模非线性响应分析,揭示地震动时空耦合特性描述参数取值变化对结构响应的影响机理;最后,基于近似技术,以产生不利的结构响应为目标,建立地震输入特性参数与结构响应之间的近似关系模型,为工程实践中基于结构特性合理设置地震输入参数与输入模式提供可靠的理论依据。本项目的研究工作对促进抗震设计理论发展有重要的实践意义。

地震动在时间和空间上的变化对大尺度结构响应产生重要影响。本项目首先提出地震动时间-空间耦合特性的表征方法,并基于密集台阵记录对地震动空间变化进行分析，构建与结构特性相关的地震动时空耦合特性数值模型；第二，在自贡架设工程尺度的流动观测密集台阵，通过数值模拟和现场实验相结合，建立了能反映土层非均匀特性影响的地震动相干函数模型;第三,基于能量一致强度包线建立了随机地震动模型，以及能够反映地震动频率非平稳特性的时-频包线函数；第四，通过引入时-频包线函数模型，建立了能够表征地震动频率非平稳特性的空间相关多点地震动拟合方法，实现了对大跨结构地震动输入特性的近似定量控制；第五，优化地震动输入方案及结构模型方案，通过对大尺度结构进行定量地震动输入的非线性响应分析,揭示地震动时空耦合特性描述参数取值变化对结构响应的影响机理;最后,基于近似技术,以产生不利的结构响应为目标,建立地震输入特性参数与结构响应之间的近似关系模型。本研究实现了对地震动特性的定量控制，研究成果对促进抗震设计理论发展有重要的实践意义。