目前国内很多重要的混凝土桥梁具有大跨、超宽的特点.结构的空间受力行为明显,从而导致混凝土的徐变效应更加复杂,一维杆系结构的徐变分析方法局限性凸显.固-壳元是一种实体退化的壳单元,兼具实体单元便于几何描述和壳单元简化结构模型的优点,适合桥梁结构的有限元建模.以固-壳元为基础,采用粘弹性理论考虑混凝土的徐变效应,结合我国04版桥梁规范中的徐变模型,拟合基于粘弹性理论的广义Maxwell模型的参数,推导了固-壳元的粘弹性本构关系,并应用于混凝土的三维徐变分析.数值分析表明,所提出的方法行之有效,受力复杂的混凝土结构有必要进行三维徐变分析.%Long span and super width are the basic characteristics of a number of bridges in China nowadays. The behavior of these structures is obviously spatial;which leads to complicated creep effect in concrete. Precise results are usually unavailable when using 1-D finite element model due to its limitation. Solid-shell element is a solid degenerated shell element;which combines advantages of both convenient geometric description for solid element and simple model for shell element. Based on solid-shell element;the creep characteristics of concrete were taken into consideration by employing the generalized Maxwell viscoelastic model. With the creep model provided in China Code of 2004 Highway P. C. Bridge;the parameters of viscoelastic model were fitted. The viscoelastic constitutive relationship of solid-shell element was derived. Numerical examples showed the validity and efficiency of the proposed method and the necessity of 3 -D creep analysis for concrete structures under complicated loading.
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