大跨度斜拉桥索塔锚固区钢-混凝土结构竖向受力机理的有限元法

A FINITE ELEMENT METHOD FOR VERTICAL MECHANICS ANALYSIS OF STEEL-CONCRETE COMPOSITE STRUCTURE IN PYLON CABLE ANCHOR ZONE OF LONG SPAN CABLE-STAYED BRIDGE

在斜拉桥索塔锚固区的钢-混凝土组合结构中,钢锚箱是通过剪力钉把大部分的斜拉索竖向分力传递给混凝土塔柱的,但两者之间的竖向传力机理相当复杂。在引入了连续化的分析方法后,使分析问题得到了简化,推导了体现组合结构竖向受力特性的基本微分方程,利用有限元方法的基本理论得到单元刚度矩阵与荷载矩阵。该文还考虑了钢-混凝土索塔锚固区施工过程的收缩与徐变效应,更好地反映了结构的实际受力特性。为验证该方法的有效性,通过工程实例与复杂的三维有限元方法进行比较,其计算结果非常相近,但该方法比三维有限元方法简单而省时,能够为实际设计提供参考。

In steel-concrete composite structure of pylon cable anchor zone in cable-stayed bridge, most of vertical component of applied cable force transfers from steel anchor box to concrete walls through shear studs, but the mechanism of vertical force transfer is complicated and remains unaddressed. After introducing the analytical continuum method, this paper simplifies the analysis problems and obtains the fundamental differential equation which can reveal the vertical mechanics of the composite structure, and then deduces the element stiffness matrix and load vectors for the finite element solution of analysis. This paper also considers the effect of shrinkage and creep on the composite structure at different construction stages in order to obtain best analysis results to describe the real structural behavior. Through an engineering design example, the method proposed in this paper is verified by a comparison of its calculation results with those obtained from complicated 3D finite element method. The proposed method is simpler and more efficient than 3D finite element method, and can be used in structural analysis.