变截面连续箱梁桥剪力滞效应的有限梁段法分析1)

FINITE SEGMENT METHOD FOR ANALYZING SHEAR LAG EFFECT OF CONTINUOUS BOX GIRDER BRIDGE WITH VARIABLE CROSS SECTION1)

  • 摘要: 为了分析变截面连续箱梁桥的剪力滞效应,提出一个4自由度的箱梁梁段单元,根据剪力滞附加挠度控制微分方程的齐次解,推导了箱梁梁段单元的刚度矩阵和等效节点力列阵,并用FORTRAN语言编写了相应计算程序。利用所编程序对已有文献中简支箱梁算例进行验算,并计算了某三跨变截面连续箱梁桥在主跨作用车道载荷时的剪力滞效应。结果表明:主跨作用车道载荷下,主跨跨中截面和中支点截面剪力滞系数分别达到1.176和1.148,在反弯点处发生正负剪力滞转变现象。

     

    Abstract: For analyzing the shear lag effect of continuous box girder bridge with variable cross section, a 4 degree-of-freedom segment element of box girder beam was proposed. The stiffness matrix and equivalent node force array of the element were derived according to the homogeneous solution of the governing differential equation with additional deflection, and a corresponding solving program was developed with FORTRAN. The program was used to calculate examples of the simply supported box girder available in the literature. The shear lag effect of a three-span continuous box girder bridge with variable cross section was computed by the present program under lane load acting on the main span. It is shown that the shear lag coefficients in the middle section of the main span and the section of middle support reach 1.176 and 1.148, respectively. It is also shown that the positive and negative shear lag transition phenomenon occurs at the inverted bending point.

     

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