大跨连续刚构桥预应力混凝土箱梁的长期挠度预测探讨

提高对混凝土收缩徐变的长期挠度预测精度，是大跨度桥梁设计中要解决的一个关键问题。根据已测得的虎门大桥连续刚构桥挠度长期观测数据，建立有限元模型，分阶段对大跨连续刚构桥预应力混凝土箱梁的徐变变形进行理论分析。探讨主梁上下缘应力差与结构徐变的关系。拟用文献1]提供的某主跨270m连续刚构桥挠度长期观测的实测数据，考虑新规范中的可变作用准永久值对理论徐变计算值进行验证，通过有限元分析对成桥后的长期徐变变形给出较准确的预测，并得出挠度长期增长系数，为此类桥梁的长期挠度预测提供依据。

Discussion about the Longstanding Deformation Prediction of Large Span Continuous Rigid Bridge Prestressed Concrete Box Girder

Increasing the long-term deflection prediction precision of concrete shrink and creep is one crucial issue that needs to be settled in the design of large-span bridges,Based on the availahle long-term deflection prediction data of Humen bridge, we analyze the creep deformation of prestressed concrete box girder of large span continuous rigid bridges in several stages theoretically by use of FEM so as to find out the relation between mid-span upper and lower edge stress dispersion and the structure creep defonnation.The analysis reveals that the long-term deflection prediction comprehensively consider the influence factors of the quasi-permanent value of changeable actions and concrete fatigue caused by cyclic load is consistent well with the in-site survey value of the 270 m continuous rigid box girder bridge ,It can offer gist to the bridge 1 ] longstanding deformation prediction of this type of bridge.