有限梁段法在变截面连续箱梁桥剪力滞效应分析中的应用

Application of Finite Beam Segment Method in Shear Lag Effect Analysis of Variable Cross-section Continuous Box Girder Bridges

为了分析变截面连续箱梁桥的剪力滞效应,选取具有2个节点、4个自由度的箱梁单元,引入剪力滞控制微分方程的初参数解,推导出箱梁梁段单元的刚度矩阵和等效节点荷载。利用FORTRAN语言编写相应计算程序,应用所编程序对某简支箱梁进行验算,并分析了某三跨变截面连续箱梁桥在主跨作用车道荷载时的剪力滞效应。结果表明:剪力滞效应对中跨1/2处影响最大,对左边跨、右边跨几乎没有影响;中跨1/2处总挠度是初等梁挠度的1.08倍。

In order to analyze the shear lag effect of a variable cross-section continuous box girder bridge,a box girder element with 2nodes and4degrees of freedom was selected.The initial parameter solution of the shear lag control differential equation was introduced,and the stiffness matrix and equivalent node load of the box girder segment element were derived.Using FORTRAN language to write corresponding calculation programs,the program was applied to verify a simply supported box girder,and the shear lag effect of a three span variable cross-section continuous box girder bridge under lane load on the main span was analyzed.The results show that the shear lag effect has the greatest impact on the mid span at 1/2,and has almost no effect on the left and right spans;The total deflection at 1/2of the mid span is 1.08times that of the elementary beam deflection.