EXPERIMENTAL INVESTIGATION ON STABILITY BEHAVIOR OF Q420 HIGH STRENGTH STEEL Y-SECTION COLUMNS

摘要

A new type of Y-section columns consisting of a steel plate welded at the back of steel angles with equal legs was put forward and subject to experimental investigation for the purpose of sectional optimization and engineering design reference. The experiments include: Material properties tests for Q420 high strength steel; Longitudinal residual stresses tests; and structural buckling tests under axial forces. Through experimental results and numerical analysis, it was concluded that: The axial buckling strength of Y-column is generally higher than that corresponds to b-category specified in code GB50017-2003. Therefore, it is safe enough to design the columns on the basis of b-category column curves; Slenderness ratio not only affects buckling strength but also has an impact on failure modes. As the slenderness increases, the failure modes generally take on local buckling, flexural buckling accompanied by torsional buckling, pure flexural buckling, respectively.