Study On Buckling Performance And Design Method Of Cold-formed Thin-walled Steel I-section Column

Cold-formed thin-walled steel is more and more widely used in the construction of water conservancy scenic area due to its advantages of energy conservation,environmental protection,recyclable materials and fast construction speed.Cold-formed thin-walled steel built-up I-section column as an important one of the members of this type of building,its stable performance and the lack of perfect theoretical analysis and design method.Through experimental research,finite element simulation and theoretical analysis,the buckling performance and bearing capacity of axial compression column with built-up I-section are studied.Firstly,the axial compression test was carried out on 56 cold-formed thin-walled builtup I-section steel columns.The design,loading device and material test of the specimen are introduced in detail,and the experimental phenomena and data are analyzed and processed.The influence of parameters such as section form,screw spacing and end constraint on the axial compression performance of the specimen is studied.Secondly,finite element software ABAQUS is used for the finite element simulation analysis of the built-up I-section axial compression specimen.The numerical analysis results are in good agreement with the test results,indicating that the finite element analysis is accurate and reliable.The parameters of fineness ratio,screw spacing and end constraints on the axial compression performance of the built-up I-section column are analyzed by using the validated finite element model.The results show that the fineness ratio has a great influence on the axial compression performance of the built-up I-section column,while the influence of screw spacing and end constraints is relatively small.Then,the effective width method of Chinese standard(GB50018-202X),and the North American standard AISI(S100-16)effective width method and direct strength method were used to calculate the axial compression bearing capacity of the section.The comparative analysis of the calculated bearing capacity shows that for the test section,the effective width method of The Chinese specification is adopted to calculate the flange width and thickness ratio,and the test piece with the flange width and thickness ratio beyond the specification tends to be unsafe.For common section members,the effective width method of Chinese standard is more conservative,and becomes more conservative with the increase of the ratio of height to thickness and the decrease of the ratio of length to fineness.The results obtained by the north American standard effective width method are in good agreement,but the results are conservative for the specimens with large web thickness and long columns.The results calculated by the North American standard direct strength method are unsafe.Finally,on the basis of experimental research,numerical simulation and theoretical analysis,the proposed calculation method which is more suitable for the cold-formed thin-walled steel built-up I-section column is put forward,and its accuracy and feasibility are verified by experimental results.