箱梁结构在偏载作用下空间网格模型探讨

Discussion on Spatial Grid Model of Box Girder Structure under Eccentric Load

混凝土连续箱梁结构是我国公路大、中跨径桥梁的常用结构型式。随着箱梁结构的不断发展,其结构体系呈现出大型化和复杂化的特点。传统的有限元模型不能计算箱梁结构在偏载作用下由于约束扭转和畸变产生的附加应力。空间网格模型是分析桥梁上部结构的一种空间分析方法,能准确计算箱梁截面各部分的正应力和剪应力。通过对福建宁古高速某箱梁结构桥梁在偏载作用下的空间网格模型研究,计算了典型截面各部位的正应力和剪应力,得出了传统偏载放大系数偏小的结论,为精确计算截面应力提供了方法。

The structure of concrete continuous box girder is a common structure used in large-middle span highway bridges in China,and as it is continuously developing,characterized by large scale and complexity.The traditional finite element model cannot calculate the additional stress of the box girder caused by the constraint torsion and the distortion under the eccentric load.The spatial grid model is a spatial analysis method for analyzing the bridge superstructure,which can accurately calculate the normal stress and shear stress of each part of the box girder section.By studying the spatial grid model of a certain box girder bridge in Ninggu Expressway in Fujian Province under the eccentric load,this paper calculates the normal stress and shear stress of each part of the typical section,and the results show that the traditional eccentric load amplification coefficient is small,which provides a method for accurately calculating the section stress.