Analysis Of Factors Influencing Long-term Deflection Of Prestressed Concrete Continuous Rigid Frame Bridge

Long-span prestressed concrete continuous rigid frame bridges have been widely used in long-span bridges in my country because of their advantages such as reasonable stress,convenient construction,smooth and comfortable driving,high structural rigidity,and good overall performance.However,long-span prestressed concrete continuous rigid-frame bridges will have long-term deflection problems in the later operation process.This problem limits the further development of long-span continuous rigid-frame bridges.For the long-term deflection mechanism of long-span continuous rigid-frame bridges The influencing factors have not yet formed a unified theory.Therefore,in order to explore the long-term deflection mechanism and influencing factors of long-span continuous rigid frame bridges.This paper takes a bridge in Guizhou as the engineering background and uses Midas finite element software to calculate and analyze the factors affecting the long-term deflection of a long-span continuous rigid frame bridge,and accumulate experience for the later deflection analysis of the same type of bridge.This article focuses on the main factors affecting the long-term deflection of continuous rigid frame bridges.Firstly,the main reasons for the loss of prestress are introduced,and the influence of the values of the friction parameters μ and κ and the loss of prestress on the deflection of the continuous rigid frame bridge are analyzed.Differences;Secondly,the mechanism of shrinkage and creep and various standard calculation model forms are introduced,and the influence of creep coefficient on the deflection of continuous rigid frame bridge is analyzed.Finally,self-weight,temperature,concrete loading age,uneven foundation settlement,The influence of relative humidity and beam cracking on the deflection of continuous rigid frame bridge.Through exploration,it is found that the longitudinal prestress loss and concrete shrinkage and creep are the main reasons for the long-term deflection of the continuous rigid frame bridge span,and the roof prestress loss has a greater impact on the deflection than the bottom prestress loss,reducing the prestress loss and The shrinkage and creep deformation of concrete is an effective measure to control the long-term deflection of the bridge;the beam cracking leads to a decrease in the structural rigidity,which further promotes the increase of the deflection;increasing the relative environmental humidity is beneficial to control the long-term deflection of the bridge.