混凝土结构三维徐变的有限元计算方法

由于传统的杆系有限元程序和公式解法不能精确考虑和计算混凝土结构的三维徐变和局部效应,因此提出了一种混凝土结构三维徐变的有限元计算方法.首先说明了三维徐变的计算原理,并对有限元计算过程中的主要模块进行了阐述.在此基础上,对一个钢筋混凝土柱算例模型进行计算,并与Dischinger公式算法进行对比;钢筋及混凝土应力、模型变形等与公式解法相差在5%以内.同时,采用该方法实现了对箍筋影响及结构局部应力分布的时变分析.最后,为分析剪切应力对徐变变形的影响,对一预应力钢筋混凝土梁进行了三维徐变计算,计算结果与试验值吻合良好.

A Finite Element Analysis Method of Concrete Structure with Three Dimensional Creep

As traditional pole system finite element method analysis and formula solution can not fully address the three dimensional (3D) concrete creep and local effect,a finite element method of 3D concrete creep is presented in this paper.First,the analysis principle and assumption are illustrated and computing process including six main components is explained with calculation flow illustrated.Then,based on this,a case model of reinforcing concrete column is analyzed; results including deformation,stress of rebar and concrete are compared with the Dischinger formula method.Also,the method is used to analyze the stirrups effect and local stress of the structure of which the distribution is time dependent.Finally,to assess the effect of shear stress to creep,a prestressed concrete beam is analyzed considering 3D creep,and the results agree well with the experiments.