基于底板束预张拉的大跨PC连续刚构桥新型合龙技术  

New Closure Construction Technology of Long-span PC Continuous Rigid Frame Bridge Based on Pre-tension of Prestressing Strand in the Bottom Slab

作　　者：胡志坚[1] 刘宇航 夏雷雷[1] HU Zhijian;LIU Yuhang;XIA Leilei(School of Transportation and Logistics Engineering,Wuhan University of Technology,Wuhan 430063,China)

机构地区：[1]武汉理工大学交通与物流工程学院,武汉430063

出　　处：《武汉理工大学学报（交通科学与工程版）》2023年第5期876-879,共4页Journal of Wuhan University of Technology（Transportation Science & Engineering）

基　　金：江西省创新驱动“5511”项目。

摘　　要：文中以萍莲高速某预应力混凝土连续刚构特大桥为研究对象,基于等效荷载法,将中跨预应力底板束预张力分解为钢束沿程竖向荷载及锚固点水平力,提出不施加配重,浇筑合龙段混凝土同时预张拉底板束消除湿重下挠效应的合龙技术.采用Midas/Civil建立有限元模型,完全模拟全桥施工阶段,将新型合龙技术与等位移配重法合龙进行对比,分析两种合龙方法成桥后全桥线形与应力差异.结果表明:新型合龙技术在不使用配重的前提下,能有效消除合龙过程中合龙口附近截面扰动,成桥累计变形值最大提升17 mm,底板压应力储备为6.31 MPa,10年收缩徐变后底板压应力为5.32 MPa,与传统方法相比压应力储备未明显减少,满足设计要求.Taking a prestressed concrete continuous rigid frame bridge in Pinglian Expressway as the research object,based on the equivalent load method,the pretension of mid-span prestressed floor beam was decomposed into vertical load of steel beam along the way and horizontal force of anchorage point.The closure technology was put forward,in which the concrete in the closure section was poured without counterweight,and the bottom plate bundle was pre-tensioned to eliminate the downward deflection effect of wet weight.Midas/civil was used to establish a finite element model,which completely simulated the whole bridge construction stage.The new closure technology was compared with the equal displacement counterweight closure method,and the difference of the whole bridge shape and stress in the two closure methods was analyzed.The results show that the new closure technology can effectively eliminate the cross-section disturbance near the closure opening without using counterweight.The maximum cumulative deformation of the bridge is increased by 17 mm,and the compressive stress reserve of the bottom plate is 6.31 MPa.After ten years of shrinkage and creep,the compressive stress reserve of the bottom plate is 5.32 MPa,which is not significantly reduced compared with the traditional method and meets the design requirements.

关 键 词：连续刚构桥 新型合龙技术 等效荷载法 钢束预张拉 合龙段施工 

分 类 号：U443.3[建筑科学—桥梁与隧道工程]