易损性分析考虑结构非线性的输入地震波选取方法研究

对于结构抗震设计和研究,地震易损性分析中输入地震波组的选择至关重要,然而现有地震波选取方法对于地震波组的多样性和离散性未作考虑或不够明确,从而影响易损性分析结果的可靠性和意义.针对这个问题,文章提出一个新的选波策略,基于目标结构的简化模型在地震波组激励下的响应,通过改进的地震动强度指标以及信息熵概念来判断输入地震波组的多样性.建立了一个3跨连续梁桥的有限元模型作为数值算例,通过执行新提出的方法验证了简化模型响应的信息熵与实际有限元模型响应的信息熵之间的关系,初步证明了此策略基于输入地震动多样性的筛选能力,可以作为地震易损性中分析输入地震动选取的简便和可靠的依据.

Selection of input ground motions for seismic fragility analysis considering structural nonlinear response

For the structural seismic design and research, the selection of the input ground motions in the seismic fragility analysis is of great significance. However, the conventional ground motion selection methods do not consider the diversity and discreteness of the earthquake group or are not clear enough, which reduces the reliability and significance of seismic fragility analysis. To solve the problem, an innovative input ground motion selection strategy is proposed from the article, based on the response of the simplified model of the target structure under the excitation of the ground motion group, and judges the diversity of the input ground motion group through an improved ground motion intensity measure and the conception of information entropy. A finite element model of a 3-span continuous girder bridge is established as the numerical case study, and the correlation between the information entropy of the simplified model response and the information entropy of the actual finite element model response is verified by implementing the proposed method. The result shows that the strategy is capable of selecting input ground motion group based on its diversity, and it could be utilized as a simple and reliable basis for the analysis and selection of input ground motions in seismic fragility analysis.