摘要
按现行规范设计的不同抗震区的结构安全性能和水平是否存在显著差异?为澄清这一问题,该文构造了一个能合理反映结构整体安全性能的承载力裕度参数,并通过承载力裕度概率密度函数的比较间接研究不同抗震区结构安全性能的差异。基于上述思路,在概率密度演化理论的框架下,由可靠度问题的不同求解方式出发,导出了承载力裕度的密度变换解及其δ序列逼近算法;然后以按规范设计的不同抗震区的四榀9层3跨钢筋混凝土平面框架为对象,结合结构非线性全过程分析和密度变换解的δ序列逼近算法,分别获得了四榀框架结构承载力裕度的概率密度函数,通过比较研究,可以发现:尽管承载力裕度的概率分布类型基本相似,但均值差异明显,反映了不同抗震区结构安全性能的差距,且随着抗震设防烈度的提高,安全水平呈下降趋势,这一现象需引起工程界的足够重视。
Are there visible differences on safety level for structures designed according to Chinese existing design codes in different seismic fortification intensity regions？ Margin ratio for ultimate limit capacity（MRULC） of structures,which is a parameter reflecting structural safety,is introduced,and then the structural safety is indicated by the probability density functions（PDFs） for MRULC.Following the idea of probability density evolution method,the transiting solution of PDF for MRULC is derived from two different descriptions of reliability,together with its approximation via a family of δ sequences.At last,taking four 9-story 3-bay reinforced concrete frames,which are designed for different seismic fortification intensity regions by codes,as examples,the PDFs of their MRULC are obtained by combining full-range nonlinear analysis with approximation via a family of sequences.By comparison,it is found that the shape of PDFs for MRULC is identical,whereas there are distinct differences for mean values,which manifest the discrepancies on safety level.What＇s more,the structural safety level decreases as seismic fortification intensity increases.And this phenomenon should be paid enough attention for engineers.
出处
《工程力学》
EI
CSCD
北大核心
2011年第2期69-74,85,共7页
Engineering Mechanics
基金
国家自然科学基金委创新研究群体项目(50621062)
重庆市自然科学基金项目(CSTC
2009BB4191)
关键词
概率结构
承载力裕度
概率密度演化理论
密度变换解
δ序列逼近
probabilistic structure
margin ratio for ULC
probability density evolution theory
transiting solution of PDF
approximation via a family of δ sequences
