Buckling Strength of Cold-Formed Austenitic Stainless Steel SHS Columns Subjected to Concentric Axial Load

초록

A study on austenitic stainless steel (STS304 TKC and STS316 TKC) square hollow section(SHS) columns subjected to centrally axial compression has been conducted to investigate the buckling behaviors of the compression members with both fi xed ends. Main variables are steel type, column length and width-thickness ratio. Buckling modes at ultimate state were classifi ed into two such as local buckling and global buckling. Compressive material properties of SHS members was also investigated through stub column tests in addition to tensile material properties. Stub columns showed local buckling mode. A fi nite element (FE) analysis model of a stainless steel SHS column considering initial geometric imperfection and compressive material properties was developed, and the validity of the FE analysis procedure was verifi ed through comparison with test results. The test buckling strengths were compared with the strengths predicted by current stainless steel design specifi cations (American Society of Civil Engineers (ASCE 8–22) and Eurocode (EC3)). As a result, it is found that design strengths with compressive material test data of stub column than those of tensile coupon were close to test buckling strength. The global buckling coeffi cients of ASCE 8–22 was the values presented for the compression members of open sections, and since it did not suffi ciently refl ect the buckling characteristics of the closed-section SHS members, some of the buckling coeffi cients were adjusted upward referring to the AISC 370–21 specifi cation. The EC3 standard presented a value with the adjusted initial imperfection coeffi cient. It was confi rmed that the predicted strength by the design equations with the modifi ed coeffi cient was close to the test and analysis buckling strength.

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