桥梁地震易损性函数中不确定性参数的影响规律分析

摘要

地震易损性函数能够考虑结构地震分析中存在的各种不确定性, 然而不确定性的量化又是当前地震易损性分析中尚未解决的问题.首先论述了国内外在地震易损性函数不确定性方面的研究现状, 并根据我国桥梁工程的实际情况, 对桥梁地震易损性函数中存在的各种不确定性进行了分类;其次讨论了各种不确定性在地震易损性函数中的处理方法;最后通过参数分析研究了不确定性对地震易损性函数的影响规律.研究表明:云图法易损性函数在同时处理多种不确定性时有一定的优势;易损性函数的均值θ越大结构失效的概率越小, 而其对数标准差β表示概率性地震分析中对结构地震响应预测均值的不确定性, β越大地震响应预测结果的精度越小.%The seismic fragility function can consider various sources of uncertainty in seismic analysis of structures.However, the quantification of uncertainty is an unsolved problem for current seismic fragility analysis.Firstly, this paper discusses the domestic and foreign research status of the uncertainty in seismic fragility function.Uncertainties in seismic fragility function of bridges are classified according to the actual situation of bridge engineering in China.Then, the treatment methods of various uncertainties in bridge seismic fragility functions are discussed.Finally, the influence of uncertainty on seismic fragility function is investigated by parametric analysis.The results show that the advantage of the cloud method is obvious in dealing with kinds of uncertainties.The larger the mean valueθof fragility function, the smaller the structural failure probability.However, the logarithmic standard deviationβindicates the uncertainty of the seismic response prediction for the structure in probabilistic seismic analysis.Therefore, the greater theβvalue, the smaller the accuracy of the seismic response prediction.