风电塔结构抗震设计的地震作用取值研究

Seismic loading for wind turbine tower structural design

本文采用均匀Poisson随机过程地震发生模型,以极值Ⅲ型分布描述地震烈度的概率分布,在考虑风电塔具有低阻尼特性的基础上,建立了不同设计使用期的地震作用计算模型,并且给出了地震烈度、地面峰值加速度与水平地震影响系数之间的换算关系。阐明了等设防烈度法,等重现期法和等超越概率法进行抗震设防烈度调整的基本原理,明确了不同设计使用期的抗震设防"三水准"。在借鉴现行建筑抗震鉴定标准中相关规定的基础上,对不同设计使用期的风电塔进行了合理的分类,利用等超越概率法分别计算不同设计基准期的风电塔的地震动。文中匹配现行抗震设计规范,列出了具体的地震作用计算步骤和计算结果。本文的研究结果不仅适用于新建的风电塔结构,也可供风电塔的抗震评估参考。

Seismic loading for wind turbine towers different design service lives were developed based on the Homogeneous Poisson Process and the Extreme Value Type Ⅲ probability distribution. The low damping feature of the wind turbine tower was considered in the model. The relations between seismic intensity,peak ground acceleration（ PGA）,and the maximum horizontal earthquake influence coefficient were provided in the paper. Basic knowledge about the equal earthquake intensity principle,the equal return period method,and the equal exceeding probability approach was described. Three levels of earthquake protection targets for different design service lives were clarified. A methodology that following the equal exceeding probability principle was proposed to estimate seismic loads for wind turbine towers with various design service lives. The corresponding results for conventional designs were listed herein. The findings in this study can be used to design a new wind turbine tower and to evaluate seismic performances of existing wind turbine tower structures.