400km/h高速铁路桥梁竖向刚度限值研究

Vertical stiffness limit of a 400km/h high-speed railway bridge

为研究400 km/h高速铁路桥梁的竖向刚度限值,首先,将铁路桥涵设计规范中不同车速的竖向挠度限值拟合外推,得到车速400 km/h时不同桥梁跨度的竖向挠度限值;然后,调整截面竖向惯性矩,实现不同桥梁竖向刚度,并考虑竖向温度变形影响,进行车桥耦合振动分析,得到不同桥梁竖向刚度下的车辆竖向加速度;最后,按规范要求在桥梁最不利位置加载得到桥梁竖向挠度和梁端转角,车辆竖向加速度达到限值时可获得竖向挠度限值和梁端竖向转角限值,并与规范预测值进行对比。结果表明,400 km/h高速铁路桥梁竖向挠度限值可采用现行规范拟合外推得到的挠度限值,梁端竖向转角限值可仍沿用现行规范限值。

To investigate the vertical stiffness limit of a 400 km/h high-speed railway bridge,firstly,the vertical deflection limit under different bridge spans at 400 km/h train speed was obtained by fitting the vertical deflection limit at different train speed in the code.Then,the vertical stiffness of different bridges was achieved by adjusting the vertical moment of inertia of the cross section.Considering the influence of vertical temperature deformation,the train-bridge coupled vibration analysis was carried out,and the vehicle vertical acceleration under different vertical stiffness of the bridge was obtained.Finally,according to the code,the vertical deflection and girder-end rotation angle were calculated by loading at the most unfavorable position of the bridge.When the vehicle vertical acceleration was reaching the limit value,the limit values of vertical deflection and girder-end rotation angle were obtained and compared with the limit value in the code.The results show that the vertical deflection limit of the 400 km/h high-speed railway bridge can use the deflection limit obtained by fitting from the current standard,and the vertical girder-end rotation angle limit can still use the current standard limit.