Research On Mechanical Properties Of A New-style Steel-web Composite Girder Bridge

With the vigorous development of China's steel industry,more and more bridge structures such as steel-concrete composite beams have been promoted and applied.Among them,composite beams with concrete tops and bottom plates have been recognized by the bridge sector with their reasonable mechanical properties and economical durability,and they have also stimulated people's potential for bridge innovation.Fence type steel web-concrete composite box girder is a new type of structure that has been optimized and improved on the basis of the excellent mechanical performance of steel-concrete composite beams.Once the structure was introduced,it was favored by its counterparts.In this paper,the structural characteristics of the new composite box girder,the stress performance,especially the shear lag and temperature effects and other key issues are studied and analyzed.Firstly,the research status of steel-concrete composite beams at home and abroad is summarized,and the mechanical properties and key problems of steel-concrete composite beams are clarified.The design concept of the steel box-type composite box girder with fences is introduced.The combination of steel bars with fences is analyzed and discussed.Beam structural performance characteristics.Aiming at the mechanical properties of concrete composite box girder with steel barrier webs,the paper analyzes and deduces the calculation formula of its resistance under the stress and limit state of elastic stage.With reference to the bridge wind-resistant design specification formula,the effect of composite steel girder bridges with box-type steel webs on the static wind loads in the transverse direction of the PC-box girder is calculated and calculated;Beam's shear lag coefficient calculation formula.The temperature gradient of the box girder is studied at home and abroad,and the temperature gradient mode is given in combination with the characteristics of the new structure to calculate the temperature effect.The results show that the temperature stress of the new structure is much smaller than that of the same size concrete box girder.The ABAQUS finite element software was used to simulate the new structural box girder bridges and general PC box girder bridges.The concrete elements were used to simulate the upper and lower floors of the concrete,and the shell elements were used to simulate the steel web structure of the fences.The box-girder bridge has a smaller moment effect and a more reasonable stress.The distribution of the beam shear force is reasonable.The shear lag coefficient of a steel sandwich beam with a fence is smaller than that of a concrete beam,and the shear lag effect is small.Compared with PC box girder,the box girder steel web composite box girder is a kind of high-quality and high-performance structure with better stress performance,lighter structure and simpler construction.