变高度连续曲线箱梁的剪力滞效应

应用能量变分原理,推导弯曲、扭转、剪力滞耦合的曲线箱梁弹性控制微分方程及其边界条件,得到微分方程的闭合解。利用所得的弹性控制微分方程的齐次解作为位移模式,应用刚度法和功能原理推导单元刚度矩阵及荷载列阵,建立一种考虑弯曲、扭转、剪力滞的曲线箱梁有限段模型。编制计算程序,对变高度连续曲线箱梁进行计算,探讨在不同荷载下的宽跨比和梁高比两个参数对剪力滞的影响,得到变高度连续曲线箱梁剪力滞效应的一些规律。进行剪力滞模型试验研究,并对模型桥进行有限段法和有限元法的数值计算,计算值与试验结果吻合较好,验证本文方法的正确性。本文所得公式是对连续曲线箱梁剪力滞效应理论的补充,分析所得结果为连续曲线箱梁的工程设计提供参考。

The shear Lag Effect on Continuous Curved Box Girder Bridges with Variable Depth

On the basis of the energy-variational principle,the differential equations and boundary conditions of a curved box girder were derived with consideration of bending,torsion and shear lag.The homogeneous solution obtained from the differential equations was used as the displacement patterns of finite segment.The stiffness matrix and load column matrixes were obtained by means of directed stiffness method and working-energy principle.A curved box girder finite segment model was established with consideration of bending,torsion and shear lag.A program is designed to calculate the curved girder bridges with variable depths.The influence of load effect pattern,width-to-span ratio,girder height ratio on the shear lag was discussed.Certain laws of shear lag effect on continuous curved box girders with variable depths were obtained.The tests of Perspex model were used to study the shear lag effects.In addition,the model tests were studied,and numerical calculations with the finite segment and finite element methods were made.The results of the model tests and numerical calculations are well matched,verifying the accuracy of the present method.The equation in this paper is the supplement to the theory of shear lag in curved box girder.The analysis results will provide useful references to engineering designs.