The Analyses Of Factors Influencing On Deflection Of Cantilever End During Process Of Continuous Girder Bridge's Structure System Conversion

With the rapid development of the theory of bridge,prestressed concrete continuous girder bridge plays more and more important role in the bridge engineering,a large number of domestic and foreign scholars on the suspended casting construction method of structural deflection of cantilever end has carried out detailed research to explore.Taking Hakka bridge as the engineering background,do some research on the deflection of cantilever end,and some useful conclusions are drawn.The main work is as follows:1.This paper give a briefly introduction of the development of prestressed concrete continuous girder bridge,the principle and characteristics of suspension casting hanging basket construction,and the theory for calculation of the deflection.2.Make an analyses of the mainly influencing factors for the change of structural deflection of cantilever end.Including: the distance between temporary support and permanent support,dismantling temporary pedestal sequence,the change of temperature,the tensioning sequence of the wire in side span area.3.An analysis has been made to find the way how the distance and order of dismantle temporary rigid fixity structure put influence on deflection of cantilever end.As well as an exploration has been made to internal force.The deflection of processes are increased first and then decreased as the increase of the distance,but the flexural deformation in the opposite direction.For total deflection of cantilever end,the greater the spacing,the larger the deflection.If the cantilever end side of structure dismissed first,the deflection under the first,and then get up;If the other way,the opposite conclusions.4.Analysis of temperature effect includes three aspects,including the process itself,before and after.The cantilever end's downwarping is 45 mm,with the "T" word structure's cantilever end downwarped only 20 mm under the influencing of the sunshine;Cooling effect take the deflection as 20 mm and 10 mm respectively.5.The deflection of cantilever end getting changed because of prestressing force.The prestressing wire including two portions,some are installed in the roof,and the others are in the floor.And different part will make different influence on the structure.More in the floor,the deflection of cantilever end is bigger;And more in the roof,smaller of the deflection,which have an opposite impact on the structure.