Study On The Shear Lag Effect Of Variable Cross-section Composite Box Girder With Corrugated Steel Webs

In recent years the box girder with corrugated steel webs is a new structure in thedevelopment of our country more quickly. Jiangsu Province, built the first domesticcomposite box girder with corrugated steel webs footbridge in2005, since then, to explore theresearch of the stress theory and construction method of our country waveform just web boxgirder bridge ushered in a the new spring. The relevant departments of the state set up aspecial Natural Science Fund, provide relevant research topic for the scientific researchinstitutions, colleges and universities. Since LanZhou JiaoTong University University takesome theory research of the box girder with corrugated steel webs in2011, through theanalysis of experimental, theoretical calculation, finite element, the paper carries out adetailed research on.This paper study on shear lag effect of the uniform box girder with corrugated steel websbased on waveform, variable cross-section rigid webs in shear lag effect of box girder isdiscussed, which is a new topic. According to the literature, the study section of the concretebox beam shear lag effect has been in a relatively mature stage, both numerical simulation andtheoretical, have obtained more satisfactory results, but research on the variable cross-sectionbox girder with corrugated steel webs in shear lag effect of box girder is still in the embryonicstage. This paper relies on the project of National Natural Science Foundation of the longspan box girder with corrugated steel webs of prestressed concrete composite box girdermechanical performance analysis and experimental research, No. project (51368032), bymeans of numerical simulation and theoretical calculation, a preliminary study of the variablecross-section of box girder with corrugated steel webs in shear lag effect. The main work andrelated conclusion:(1) build a (3m+3m) continuous beam finite element model in accordance with theproject test, in different conditions, compared with the shear lag effect of composite boxgirder with corrugated steel web and variable cross-section of box girder with corrugated steelwebs, found that they do have very big difference, the shear lag coefficient of variable sectionwith corrugated steel webs in box beam and section form is closely related to the conclusion.(2) according to the bridge design specifications, and explore the shear lag effect of twolane and three lane550kN vehicle loads of box girder, the lateral arrangement of load has agreat influence on the shear lag effect of box girder of conclusion, a greater place in load,shear lag effect of box beam is bigger, also found that the diaphragms also influence the shearlag effect of box beam.(3) the main factors influencing the width span ratio is the shear lag effect of box girder,this paper established the different width variable cross-section of corrugated steel webs combined finite element beam model of cross ratio, were studied. The concentrated load anduniformly distributed load, the influence degree of wide span to depth ratio on the shear lageffect of box, the shear lag coefficient of variable section composite box girder under differentload cases with the wide span ratio increases.(4) diaphragm position (distance) influence on the shear lag coefficient is more obvious,this paper discusses the different diaphragm position (distance) maximum shear lagcoefficient and position of box girder, the diaphragm can effectively reduce the optimalposition of box beam shear lag coefficient and horizontal partition layout conclusion.(5) because of different loads, beam axial stress distribution is different, namely the boxbeam shear lag effect in the axial distribution is different, this is also the main basis for thedetermination of box beam shear lag position of maximum, in the diaphragm position stressappears obvious mutation; under concentrated load, the maximum shear lag is the position ofloading position (ignoring the effect of diaphragm when), uniform load generally appears inthe center of the span (ignoring the effect of diaphragm plate), and the shear lag coefficient islarger than the shear lag coefficient of roof plate.