拱脚结构的模型实验与有限元分析

本文应用环氧树脂材料浇铸成某大跨度桥梁预应力拱脚模型,采用精密铸造成型方法做出模型中的四条索道孔。用自行研制的传感器施加四条模拟钢索的索力,通过专门设计的加载装置,使用精确的滑轮导向,在5个截面上分别施加剪力Q、弯矩M和轴力N,并考虑自重载荷,进行了电测模型实验。应用ANSYS软件对拱脚实际结构进行了有限元分析,根据模型实验时索与索道孔壁的接触情况建立了力的边界条件,使有限元计算与真实情况接近,计算误差大为减小。同时将实验与有限元分析结果进行了比较,变化规律一致,数值较为接近。对拱脚的优化设计提供了重要的参考依据。

Model Experiment and Finite Element Analysis for the Stresses on the Structure of Arch Foot

The stress distributions in the prestressed arch foot of a long-span bridge were investigated with strain gage technique using epoxy resin model.Four ropeways in the arch foot model were made with the method of precision casting,and four forces in the ropes were applied with sensors designed by ourselves.With the loading equipment devised specially,the shear force Q,bending moment M and axis force N were loaded on five sections by accurate pulley guide respectively.The self-weigh load was also taken into account.The actual arch foot structure was also analyzed with finite element program ANSYS.According to the situation of model experiment,we proposed the loading boundary condition of the contact condition between the rope and ropeway wall.And with the boundary condition the finite element computation model is close to the actual condition,the computing error is reduced greatly.After comparing the experimental data to the finite element results,it is shown that the test data from experimental stress analyses agree well with the results calculated by finite element method.And the results obtained provide reference basis for optimizing the design of arch foot.