Study On The Shear Lag Effect Of Wide Box Girder In Extradosed Cable-stayed Bridge

Extradosed cable-stayed bridges are different from both cable-stayed bridge andcontinuous girder bridge. The stress distribution of section in wide and thin box girder doesnot conform to assumption of the plane section and stress in transverse is uneven, which showthe shear lag effect. Scholars have engaged in researching shear lag effect and attained somemeaningful outcomes which solved small part of problems in engineering. This thesis takeMian Xian han jiang bridge for example and background to research the shear lag effect ofwide box girder of extradosed cable-stayed bridge, main contents are as follows:1、Introduce the development history and the development situation both at home andabroad and its characteristics of extra dosed cable-stayed bridge briefly.2、Firstly, introduce research status of the shear lag effect briefly. Then, introduce manycomputing methods and experimental study situation of shear lag effect.3、Introduce a widely used in engineering and simple method called three bar simulationanalysis. Then, explain its basic ideas of solving the box girder shear lag effect in detail.According to boundary conditions and load conditions deduce the theoretical calculatingformula of three bar simulation analysis to calculate some key section shear lag coefficient ofthin-walled box girder in practical engineering.4、The longest cantilever construction stage model was built with spatial finite elementanalysis software. Then analyze and calculate shear lag effect of the longest cantileverconstruction stage of extradosed cable-stayed bridges. More spatial finite element analysismodels were built to analyze the possible influencing factors of box girder about shear lageffect such as prestress loss, diaphragm thickness and diaphragm distance.Some rules are asfollows:(1)、Prestress loss and diaphragm thickness has little influence to the shear lag effect ofroof and floor of box girder, which can be neglected(2)、Diaphragm distance not only influence the stress but also the shear lag effect of roofand floor of box girder along cross section, which can not be neglected...