Research On Bending Property Of The Prestressed Concrete Box Girders With Corrugated Steel Webs

PC composite box girder with corrugated steel webs is a new type of bridge. It reduces the self-weight that corrugated steel webs are used to replace the traditional concrete web. Compared with traditional PC box girder, the PC composite box girder with corrugated steel webs has superiority economy benefit and social benefit. It has reasonable mechanic property, structural material has the opportunity to bring into fully play and the structure accord with the light-duty demand.PC composite box girder with corrugated steel webs was used extensively overseas. The research productions and design methods in existence in our country couldn't satisfy the demand of engineering practice. So the research of PC composite box girder with corrugated steel webs is very exigent.In this paper, the bending property of PC composite box girder with corrugated steel webs was studied. A testing model with one-to-four scale was made to research the mechanical properties of the composite box girders. The deflections of the key sections, the unit elongation strains of the corrugated steel webs, the top and bottom concrete slabs and the ordinary reinforcement steels and the values and varying rules of the reaction were tested under the static loads to all levers. The cracking load and the failing load were obtained by the experiment. The results analysis by finite element method was compared with the testing results.It was approved that the strain distribution of concrete slabs of the composite box girder with corrugated steel webs accord with the dummy even section assumption. The shear lag of box-girder with corrugated steel webs appeared at the top and the bottom flange under the symmetrical load and asymmetrical load. The shear lag effect was notable at the loading sections.The mechanical process of model girder included elastic stage, working stage with cracks and yielding stage. It was different from the traditional PC box girder that the girder could continue bear the weight after the bars in the bottom flange yielding. The cracks could be controlled and the employ efficiency could be improved by adjusting the quantity of bars in the bottom flange. The semi-empirical formula of carrying capacity of PC composite box girder with corrugated steel webs was deduced by model testing and finite element analyses. The analysis results showed that the precision of the formula could satisfy the demand of design. The bending design method of PC composite box girder with corrugated steel webs was given, and structural check computation was done.