| With the rapid development of steel structure buildings in China,steel structures have been widely used in various industrial plants,large venues,shopping malls and other architectural fields.Among them,the portal steel structure factory building is a relatively common steel structure building.The portal steel structure factory building is generally composed of a rigid frame,a supporting system,and an enclosure structure.The portal frame is a very important part of the portal steel structure workshop,in which the H-shaped steel column is one of the main force-bearing components.However,in order to make full use of the properties of the cross-section materials,the steel structure is designed to make the "stress ratio" of the H-shaped steel column relatively large,and it is characterized by long and thin on the steel structure members.These characteristics are easy to cause some initial defects in the H-shaped steel column during the construction process,such as: column foot elevation error,axis offset,steel column bending and tilt,etc.These initial defects will have a certain effect on the stress,displacement and stability of the structure.At present,there are few research reports on this issue at home and abroad,lack of in-depth analysis of the impact of this problem on the structure and the pre-control and treatment of the impact of the structure under various initial defects.Therefore,research on the initial defects of H-shaped steel columns is of great significance to the development of portal steel structure workshops.Initial stress and initial displacement are important indicators caused by initial defects in the installation of H-shaped steel columns.In this paper,based on the design characteristics of the portal steel structure plant and the requirements for the installation deviation of the H-shaped steel column in the portal steel structure plant in various specifications,combined with the transportation and installation methods of the H-shaped steel column,several typical initial defects and initial defect combinations.Theoretical calculation and analysis of these initial defects and combinations,combined with the large-scale finite element analysis software ABAQUS to establish a model,simulate the initial defects in the portal steel frame and analyze the maximum initial stress and maximum initial displacement generated by the initial defects and the initial defect combination Happening.This article mainly carried out the following research: 1.combined with the design characteristics of the door steel structure and the H-shaped steel column construction process,analyzed and selected four kinds of initial defects generated during the installation process.2.Theoretical calculation analyzes the characteristics of the four initial defects and the maximum initial stress without considering the weight of the structure.3.Use software to simulate the maximum initial stress of a single initial defect in a single-span and double-span structure under the weight of the structure,and compare and analyze with the theoretical calculation.4.Through comparative analysis,find the initial defect combination of the most unfavorable factors.5.Use the finite element analysis software ABAQUS to analyze these initial defect combinations,find out the rules of initial stress and initial displacement caused by the initial defect combinations,and compare with the situation of a single initial defect.6.Analyzed the influence of the stress and displacement generated by these initial defect combinations on the structure of the portal steel building.7.Explore the deviation of the initial defect combination when the stress on the structure reaches the strength required by the specification.The following results are obtained through research: 1.The structure's own weight will cause the impact of the initial installation defects of the H-shaped steel column on the structure.2.The location of initial installation defects of H-shaped steel columns is different,and their impact on the structure is also quite different.3.For some initial defects,they do not generate initial stress when they appear alone in the structure,but when they appear in the structure at the same time as other initial defects,the impact on the structure will change greatly.4.The same initial defects combined in different height H-shaped steel columns have different effects on the structure.As the height of the steel column increases,the initial stress generated by the initial defect combination decreases and the initial displacement increases.5.The initial defect combination in the single-span structure has a greater impact on the stability of the structure than the double-span structure.6.When the stress on the structure reaches the strength design value,the offset of the initial defect combination of single-span and double-span structures is greater than the allowable value of the specification.Figure[49] table[24] reference[55]... |
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