| As a new type of steel-concrete composite structure,the corrugated steel web composite box girder has the advantages of reducing structural weight and reducing web cracking.The fabricated corrugated steel web box girder not only maintains the advantages of the integral structure,but also ensures the good integrity of the fabricated structure by connecting the segments with epoxy resin.The construction technology of segmental prefabrication and assembling greatly saves the construction period and improves the economic efficiency,which is expected to become the future development trend of my country.Based on the above background,this paper,relying on the Natural Science Foundation of Hebei Province,has carried out research on the mechanical properties of the assembled corrugated steel web composite box girder.The main work and research results are as follows:(1)Through the model test,analyze the bending force characteristics of the integral and assembled corrugated steel web composite box girder in the elastic stage,and study the strain distribution of the top,bottom plate and steel web along the section height direction.The shear lag effect of the integral beam under the action of single-point concentrated loading and three-point loading is discussed.(2)The deflection distribution law of the assembled corrugated steel web composite box girder along the bridge axis under symmetrical loading and eccentric loading is studied,and the effect of the segmental joints on the deflection of the beam is analyzed.The change law of load increase,and the prestress increment value in the limit state;The distribution law of the lateral internal force of the fabricated beam under different loading conditions in the elastic stage is analyzed.The analysis shows that in the design of this type of structure,the influence of the web on the shear lag effect and the lateral internal force distribution should be considered.(3)Through the whole process test research of the symmetrical loading force of the integral beam and the fabricated beam,the comparison test results show that the ultimate bearing capacity of the fabricated beam is reduced compared with the integral beam,but the deformation is smaller than that of the integral beam,and it has good resistance.The ability to shape and deform.In the whole process,the joints are well connected,which can better maintain the integrity of the structure.The cracks of fabricated beams mainly appear in the places where the section steel bars are not arranged.Compared with the integral beams,the cracks of the bottom plate are less and the width is smaller.(4)Relying on the three-dimensional finite element model,through parameter analysis,the influence of the number of segments and the thickness of the glued joints on the flexural performance and flexural rigidity of the assembled corrugated steel web composite box girder is discussed.The following conclusions are drawn:increasing the number of sections will result in a reduction in the bending resistance of the structure,increasing the number of chambers can effectively reduce the shear lag effect of the structure,and increasing the thickness of the glue layer will increase the deformation of the structure and reduce the bending of the structure.Stiffness.(5)Based on the existing theoretical analysis,the calculation method of the external prestress increment of the assembled corrugated steel web composite box girder is deduced,and combined with the classical bending theory,the ultimate flexural bearing capacity of the corrugated steel web prestressed composite box girder is checked.The formula was revised,and the calculation formula for the ultimate flexural bearing capacity of the assembled corrugated steel web composite box girder considering the external prestress increase and the force of the corrugated steel web and not considering the force of the section reinforcement was put forward.Provide practical calculation methods for simplified calculation of engineering design. |
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