EXPERIMENTAL STUDY ON THE BUCKLING BEHAVIOR OF Q420 HIGH STRENGTH STEEL WELDED TUBES UNDER AXIAL COMPRESSION AND DESIGN METHODS

The axial compression column test was conducted to investigate the overall buckling behavior of Q420 high strength submerged-arc welded steel tubes under axial compression, including 15 specimens. Based on the test results, the characteristics of buckling deformations were summarized and the relationship about buckling coefficients between the 15 test results and the Chinese code curves were compared, and the reliability of the finite element models was validated. Based on the calculation results of the parametric analysis using the finite element models, the buckling coefficients from the 60 calculated results of the finite element analysis and the Chinese code curves were compared. Finally, this paper proposed two kinds of suggestions about the overall buckling design method of the Q420 high strength submerged-arc welded steel tubes: one is for the choice of column curves in the Chinese code, that is, members under axial compression could be calculated as class-a section for its buckling capacity; the second suggestion was that a new column curve was suggested, in which the calculation parameters α₁, α₂, α₃ to calculate the buckling coefficient φ of Chinese design code were updated.