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针对现行可靠度设计统一标准给出的荷载分项系数值对应可变荷载效应比值取值范围较低,缺乏对该荷载分项系数值在可变荷载效应占高比重下适用性的充分考虑的情形,以钢拱架结构模型和RC框架柱模型为例,分析了可变荷载效应比值的取值范围,揭示了可变荷载效应比值将会较高的现象;基于可靠度理论并结合设计约束条件建立了荷载分项系数的计算方法;通过数值分析,求解得到了荷载分项系数值;最后分析了按多国规范用荷载分项系数进行结构设计的可靠指标随可变荷载效应比值的变化规律。结果表明:可变荷载效应占高比重时,按我国规范用荷载分项系数设计的混凝土和钢结构构件的可靠指标低于目标可靠指标较多;而美英两国规范用荷载分项系数的适用性要好于我国规范,但对应的钢结构构件的设计可靠指标仍偏低。从可靠性的角度为近年风、雪灾害中若干结构容易破坏的现象提供了补充解释,同时也为相关规范修订提供参考。
In view of the current reliability design uniform standard gives the value of the load component coefficient value corresponding to variable load effect ratio range is low, the lack of full consideration of the applicability of the variable load factor under the high proportion of variable load effect Taking the steel arch structure model and the RC frame column model as an example, the range of the value of the variable load effect is analyzed to reveal the phenomenon that the ratio of the variable load effect will be higher. Based on the reliability theory and the design constraints The calculation method of the load partial coefficient is established; the numerical value of the load partial coefficient is obtained through the numerical analysis; finally, the variation of the reliable index of the structural design with the variable load effect ratio according to the multi-national standard load partial coefficient is analyzed . The results show that: when the variable load effect accounts for a high proportion, the reliability index of concrete and steel structure components designed according to the normative load factor in China is lower than the target reliability index; and the applicable load sub-coefficients in the United States and the United Kingdom are applicable Sex better than our standard, but the corresponding design of steel structural components is still low reliability indicators. From the reliability point of view, it provides a supplementary explanation for the phenomenon that some structures in the wind and snow disasters are easily destroyed in recent years, and also provides a reference for the revision of relevant norms.