Research On Shear Lag Effect Of Three Cells Single Box Girder In Long-span Variable Cross-section Continuous Beam Bridge With Corrugated Steel Web

Since the21st century, with the rapid development of composite girder bridge, Boxgirder with Corrugated steel was widely used. On the basis of previous research and designcode of some countries, the dissertation presented systematical study on shear lag effectionfor long-span variable cross-section of single box three cells in continus girder bridge withcorrugated steel web through theoretical derivation and finite element analysis. The mainworks involved in this research are as follows.Firstly, the history and the state-of-the-art in bridge engineering are introduced, secondlybase on regular in shear deformations of wide flanges, method for defining functions ofshear-lag warping displacement in single box three cells composite section with corrugatedsteel web is presented. The principle of minimum potential energy in Energy VariationMethod is used in deducing computational formula of longitudinal normal stress and shear lagcoefficient in flanges of three-span continuous bridge that is single box three cells compositesection with corrugated steel web,which is under Concentrated load and Uniformly distributedload respectively.Secondly, the long span variable cross-section composite continuous box girder bridgewith corrugated steel webs named Fenghua River Bridge, stress distribution and shear lagcoefficients of key sections under concentrated load, uniform load and actural loads wereanalysised. the shear lag effect is more serious in critical midspan position and bottom flangecalculation point. The longitudinal normal stress obtained the theoretical calculation formulawas checked. Under concentrated load and uniform load distribution of maximal shear lagcoefficient in bottom flange along the longitudinal position of the girder was analyzed.The parameter analysis for shear lag effection of the key cross-section in three-spancomposite section bridge with corrugated steel web which is single box with three cells isanalyzed, and Wide span ratio, Aspect ratio,inside and outside roof cantilever slab ratio are asshape parameter considered. Then empirical fomulas of shear lag coeffection are raised basedon sensitive parameters in different key sections respectively.Finally basing on reciprocal relationship of effective distribution width ratio andmaximum shear lag coefficient in flanges, empirical fomulas of effective distribution widthwhich is suited for composite section bridge with single box three cells in Top and bottomflange plate is raised.