Analysis And Experimental Study On Shear Lag Effect Of Box Girder With Corrugated Steel

Composite box girder with corrugated steel slabs,which common reinforced concrete slabs is replaced by corrugated steel slab, has superior mechanical properties and numerous advantages.However, the shear lag effect has attracted much attention.This paper focuses on the problem of the shear lag effect of composite box girder with corrugated steel slabs.The experimental study and finite element method are used to analyze the difference shear lag effect between prestressed concrete box girder and prestressed concrete composite box girder bridge with corrugated steel slabs.The main work and research conclusions are as follows:(1) Distribution of shear lag effect of prestressed concrete composite box girder with corrugated steel slabs is analyzed:By using ANSYS software as a platform,the finite element analysis model of two kinds of box-girders are established.The transverse distribution of shear lag effect of composite box girder with corrugated steel slabs is analyzed. The results show that the cross section is the positive shear lag effect.(2) The differences of distribution of shear lag effect between two kinds of box girder are analyzed:Based on the finite element theory, The transverse and longitudinal distribution rule of shear lag effect has been analyzed between two kinds of box girders under the same parameters.Analysis show:The transverse shear lag effect distribution between the two kinds of box girders are approximately the same. But under symmetrical load and eccentric load, the shear lag effect of the prestressed concrete composite box girder with corrugated steel slabs is weaker than that of the ordinary prestressed concrete box girder on the top plate;Under symmetrical load, the shear lag of the former is stronger than that of the latter. The shear lag effect of the two box girder is obvious near the load position.(3)A comparative analysis of the structural parameters between two kinds of box girder:Based on the finite element theory,some structural parameters are analyzed. The effect of the width span ratio on the shear lag effect of the two box girders is the biggest. Span height ratio has great influence. Under the same width span ratio,the shear lag effect of prestressed concrete composite box girder with corrugated steel slab box girder is weaker than that of common prestressed concrete box girder.The shear lag effect of the top plate of the concrete box girder with span height ratio is more obvious than that of the prestressed concrete composite box girder with corrugated steel slabs.The change of the span height ratio and the concentrated load has little effect on the shear lag effect of the box girder with corrugated steel slabs;Under the same concentrated load, the shear lag effect of the ordinary prestressed concrete box girder is stronger than that of the prestressed concrete composite box girder with corrugated steel slabs;The outer (inner) bearing length change has little effect on the shear lag effect of the box.(4)Experimental study on the distribution of shear lag effect between two kinds of box girders:Making one composite box girder with corrugated steel slabs and one common concrete box girder.This article selects some experimental data. It compares the difference between the test value and the finite element value.Theσz of A measuring points under different size concentrated loads have different degrees of change.The σz of B measuring points-are roughly linear,and the changes are not obvious.The test value of box beam shear lag is agreement with the finite element method, and the result of finite element analysis is reliable.(5) A comparative analysis of the experimental data between two kinds of box girder:The test results also show that under the same load, the shear lag effect of prestressed concrete composite box girder with corrugated steel slabs is lower than that of ordinary prestressed concrete box girder, and the shear lag effect of the former is higher than that of the latter.