反向预应力张拉托架预压施工技术

摘要

以资兴高速公路青云大桥为施工背景，当桥梁在高墩或受其它因素影响的情况下无法正常实施传统的砂袋或预制混凝土块预压时，采用将拼装好的挂篮主桁架系统在地面利用千斤顶和钢绞线等张拉设备，运用应力张拉原理进行分级加载预压以达到预压效果。通过建模进行有限元受力分析，分析验证托架系统各受力结构的强度、刚度；通过对托架预压，验证托架实际受力产生的变形，消除非弹性变形，同时为正确设置预拱度提供可靠的数据。%Taking the Qingyun Bridge construction of Ziyuan-Xingan Highway as a background,when the bridge could not be properly implemented the traditional sand bags or prestressed concrete blocks preloading in high pier or affected by other fac-tors,we use the hanging basket main truss system which has already been assembled on the ground with jack and steel strand tensioning device,the stress tension principle is applied to carry on the step by step preloading in order to achieve the effect of preloading.By modeling the finite element stress analysis,the strength and stiffness of each bearing structure of the bracket system are analyzed and verified.By means of the prepressing of the bracket,the deformation of the actual force of the bracket is verified,the inelastic deformation is eliminated,and the reliable data for the correct setting of the pre-camber is provided.