斜拉桥空间有限元精细化建模技术研究

Technical Study of Spatial Finite Element Fine Model for Cable-Stayed Bridge

斜拉桥是桥梁结构中比较复杂的一种,由于有塔墩和斜拉索的作用,结构处于高次超静定状态。斜拉桥结构分析以往大多采用平面杆系模型或三维梁格单元模型,很少有人采用索单元和三维实体单元建立斜拉桥全桥模型进行结构分析。采用梁格单元模型分析斜拉桥无法准确模拟主梁抗扭刚度、剪力滞、偏心荷载作用等,在做斜拉桥荷载试验时很难获得全桥任意车列荷载作用下,空间位置测点的理论计算结果。本文将详述利用交通部公路科学研究院开发的桥梁检测分析系统QLJC建立斜拉桥的索单元和实体单元组合的精细化斜拉桥有限元全桥模型,其中拉索用2节点索单元离散,主梁和塔墩用实体单元离散,拉索、主梁和塔墩单元之间通过节点位移约束方程连接。采用的实体单元是12节点等参元,它更适合于桥梁这种横向尺寸小纵向尺寸大的细长结构,这是一种切实可行的斜拉桥空间分析方法。本文给出了一些动静力分析的结果。

The cable-stayed bridge is more complex structure in bridge. Because of its pylon and cable,cable-stayed bridge is state of high hyperstatic structure. Analysis for cable-stayed bridge used 2D or 3D beam element model routinely. Only few researcher used 3D solid element and 2 nodes link element to set up full bridge element model of cable-stayed bridge for structure analysis. It is impossible to simulate accurately about beam rotation rigid-ity,shearing anelasticity and eccentric load action etc. It is difficult to get calculating results of survey point in space position when load test for cable-stayed bridge under random vehicle arrange action. This pepper introduce to make use of software of Analysis System of Bridge Testing （ Chinese name abbr. QLJC）,which is developed by RIOH （Research Institute of Highway） of China,to set up full bridge element fine model of cable-stayed bridge with 3D link and solid element. 3D solid element is isoparametric element with 12 nodes,which is more fit for bridge structure of slim structure with small size on cross section and large size on longitudinal section. Girder and pylon of cable-stayed bridge are meshed with 3D solid element. Cable is meshed with 2 nodes 3D link element. Girder,pylons and cables are connected with restricted equation of node displacements. This is a feasible spatial analysis method for cable-stayed bridge. Some calculating result of static and dynamic analysis will be put out in this pepper.