非均匀收缩对大跨径连续刚构桥长期变形的影响  

Influence of Differential Shrinkage on Long-Term Deflection of Long-Span Continuous Rigid Frame Bridge

作　　者：张运涛[1] 孟少平[2] 刘安中[1] 

机构地区：[1]安徽建筑工业学院土木工程学院,安徽合肥230022 [2]东南大学混凝土及预应力混凝土结构教育部重点实验室,江苏南京210096

出　　处：《西南交通大学学报》2011年第3期379-384,共6页Journal of Southwest Jiaotong University

基　　金：江苏省交通科学研究计划资助项目(05y02);交通部科技攻关资助项目(20063180001)

摘　　要：为了充分考虑非均匀收缩对大跨径混凝土连续刚构桥长期变形的影响,基于平截面假定,导出了等效收缩应变的计算公式.采用杆系有限元程序,对苏通大桥连续刚构由于截面非均匀收缩引起的长期变形进行了计算,并用降温法模拟等效收缩应变.分析结果表明:考虑截面非均匀收缩后,苏通大桥连续刚构主梁跨中的长期挠度比传统的不考虑非均匀收缩的方法增大6.0 cm,其中由于顶底板厚度差异引起的长期挠度达5.5 cm,截面配筋差异引起的长期挠度为0.5 cm;对于大跨径混凝土箱梁桥,桥梁预拱度设置时应考虑截面非均匀收缩对挠曲变形的影响.In order to fully consider the influence of differential shrinkage on the long-term deflection of a long-span continuous rigid-frame concrete bridge,formulas for calculating equivalent shrinkage strain were deduced based on a normal section assumption.Bar-system FEM（finite element method） was used to calculate the long-term deformation of Sutong continuous rigid-frame bridge due to differential shrinkage,and the equivalent shrinkage strain was simulated with the cooling method.The research results show that when the effect of differential shrinkage is considered the deflection at mid-span of Sutong continuous rigid-frame bridge is 6.0 cm larger than that based on the conventional method.The long-term deflection due to differential shrinkage resulted from different thicknesses of flanges is up to 5.5 cm,while it is only 0.5 cm due to differential shrinkage resulted from different ratio of reinforcement.The deformation due to differential shrinkage is significant and should be considered in camber setting of long-span concrete box girder bridges.

关 键 词：连续刚构桥 长期变形 非均匀收缩 理论厚度 配筋率 等效应变 

分 类 号：U448.35[建筑科学—桥梁与隧道工程]