斜拉式桁架桥节点局部应力分析

Local Stress Analysis of the Node of Oblique-pulling Truss Bridge

斜拉式桁架桥是一种结构形式新颖的桥梁,其节点处多根杆件交叉,并有预应力钢筋通过,混凝土受力复杂而容易开裂.文中以工程实例为背景,建立了节点处的三维有限元模型,采用有限元程序对节点处的应力分布进行了分析.分析表明:只要构造合理,就能保证节点应力分布均匀,混凝土应力满足规范限值要求,但在预应力钢筋锚头下以及下弦杆截面突变处的小范围内存在一定的应力集中,在设计以及施工中值得注意.

Oblique-pulling truss bridge is a new kind of bridge and the related research is quite limited. Several beams are intersected at the joint and tendons are passed through the joint as well, which make the local stress distribution of the joint complex and as a result the joint is prone to crack. Based on an engineering example a FEM model of the joint is established and the local stress distribution is analyzed with the help of finite element software. Analysis results indicate that the local stress distribution of the joint is fairly uniform and the stress of the concrete meets the code of the Chinese bridge engineering design criterion, but stress concentrations exist in the region under the anchorage head and the region where the section of the lower chord has a sudden change, which need be paid enough attention during the design and construction.