Seismic fragility analysis, which quantitatively describes the dynamic relationship between earthquake intensity and structural failure probability, plays an important role in the overall seismic risk assessment. An appropriate structural demand model can significantly improve the efficiency of seismic fragility analysis, and currently the most commonly used model is the lognormal model. However, recent studies have shown that this model's rationality is still in doubt. In this study, a novel structural demand model for generating analytical fragility curves in the form of a three-parameter lognormal distribution is proposed and investigated based on a large amount of nonlinear dynamic analytical data using observed Japanese ground motions with a wide range of magnitudes and epicenter distances. It shows a better fitting effect than the existing lognormal model on structural demand distribution and is expected to be more applicable to seismic fragility analysis. Through numerical fragility analysis examples on two common structural types, i.e., a steel frame structure and a reinforced concrete frame structure, the accuracy and feasibility of the proposed model are proven.

地震脆性分析定量描述了地震烈度与结构破坏概率之间的动态关系，在整体地震风险评估中起着重要作用。适当的结构需求模型可以显着提高地震脆性分析的效率，目前最常用的模型是对数正态模型。但是，最近的研究表明，该模型的合理性仍存在疑问。在这项研究中，提出了一种新颖的结构需求模型，该模型以三参数对数正态分布的形式生成分析脆性曲线，并基于大量非线性动态分析数据，使用观测到的日本地震动，幅度范围和幅度范围广，并且对该模型进行了研究。震中距离。与现有的对数正态模型相比，它在结构需求分布上显示出更好的拟合效果，并有望更适用于地震脆性分析。通过对钢框架结构和钢筋混凝土框架两种常见结构类型的数值脆性分析实例，证明了该模型的准确性和可行性。