| With the gradual increase of China’s requirements for the development of green building and assembly-type building,the attention to steel structure building is obviously enhanced,and various new materials and new cross-sectional forms of members are gradually appearing and used,therefore,this paper introduces a collocation column made of three hot-rolled H-beams spliced by high-strength bolts,which can effectively reduce carbon dioxide and harmful gas emissions during the welding process,and the construction process The construction process is convenient and fast,which is very much in line with the characteristics of rapid installation of assembled structures.As the shaped column can show better mechanical properties,scholars at home and abroad have made a lot of research on this,but at this stage,the main focus is still on the welded hotrolled steel shaped column,and there is less research on the hot-rolled steel spliced column.In this paper,the axially stressed high-strength bolt build-up I-shaped columns are studied in depth.The main work contents and conclusions are as follows.1.ABAQUS finite element analysis software was applied to simulate and verify the existing angle-steel plate build-up I-shaped columns,and compare the load-axial displacement curve and the error size of peak load obtained from axial pressure test and finite element simulation analysis to ensure the correctness and reliability of the finite element analysis method.2.The finite element model of the axially stressed high-strength bolt build-up I-shaped columns are established and divided into three types according to the flexural mode: overall bending flexure around X-axis,distortion-integral correlation flexure around Y-axis and local flexure.In addition,the critical load of the distortion-integral buckling member is similar to the calculated value of Euler’s formula,and the distortion-integral buckling is regarded as the overall bending buckling around the Y axis.The reasonable ratio of bolt spacing to member length is determined to ensure the mechanical performance of the member while taking into account the convenience of the construction process and economic reasonableness.3.The effects of member steel strength,initial defects and peak residual stresses on the stable load carrying capacity of axially stressed high-strength bolted build-up I-shaped columns were analyzed.The results show that the steel grade,the initial geometric defect amplitude and the peak residual stress have a large influence on the overall stability coefficient of the member.4.For the high-strength bolt build-up I-shaped columns where overall buckling occurs,the results obtained from finite element analysis are compared with the column curves of Chinese standard GB50017,European norm EN 1993-1-1 and American norm AISC 360-16,and corresponding design methods are proposed according to the different types of column curves.The applicability of the stability coefficients of axially stressed high-strength bolt build-up Ishaped columns to the column curves of various countries is also evaluated,and the column curves conforming to such cross-sections are fitted and design methods are proposed according to the computational form of column curves in the national standard GB50017.5.For high-strength bolted I-shaped columns with local buckling,the direct strength method of the American code was used as the basic method for predicting the ultimate load carrying capacity of such members,considering the complexity of the member cross-section.It was found that the results calculated by the direct strength method of the American code differed significantly from the local buckling capacity obtained by the finite element analysis.Therefore,a new modified calculation formula is proposed and the applicability of the new formula is evaluated. |
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