核电站混凝土结构弹塑性地震楼面响应谱分析

核电站安全相关混凝土结构的抗震分析和设计主要基于线弹性假定,不考虑材料的非线性特征和钢筋同混凝土之间的黏结滑移效应。实际上,核电站运行若干年以后,随着结构的老化,弹塑性特征会逐步显现。以一榀单跨两层足尺实验框架为研究对象,采用纤维梁单元,分别采用线弹性模型和弹塑性模型计算楼面响应谱并同实测值进行对比。分析表明:对在役核电站地震响应评估,应该充分考虑混凝土结构的弹塑性特征,合理地评估结构地震响应和楼面响应谱特性,从而为核电站设备、系统和部件的地震安全评价提供可靠依据。我国早期投运的核电站运行已经超过20年,分析方法和结论对在役核电站地震安全评估有较好的参考价值。

ANALYSIS OF SEISMIC FLOOR RESPONSE SPECTRA OF ELASTOPLASTIC RC STRUCTURES OF EXISTING NUCLEAR POWER STATIONS

The seismic analysis and design of safety-related concrete structure of a nuclear power station are mainly based upon linear elastic assumption,without consideration of the non-linear features of the material and the bond-slip effect between steel reinforcement and concrete. Actually,after years of operation of a nuclear power station,its aging structure has been of the elastic-plastic feature gradually obvious. Taking a two-story experimental frame as its study object as well as adopting fibre beam element,it was calculated floor response spectra by using linear elastic model and elastic-plastic model respectively and then a comparison between the tested value was done. The results showed that elastic-plastic feature should be fully considered in the seismic response evaluation of nuclear power station in operation,so as to reasonably evaluate structure seismic response and floor response spectra,thus providing a valid basis for seismic re-evaluation of nuclear power equipment,system and component. In China,it's been 20 years since the earliest nuclear power stations have been put into operation,the analytic methods and conclusion of this paper would serve as useful reference for seismic safety evaluation of nuclear power stations in operation.