Global buckling investigation of T-shaped built-up columns composed of two hot-rolled H-shapes

Hot-rolled H-forms are used sparingly in the building industry in China, and there is a vast supply of these shapes. In Chinese academic circles, the utilization ratio of hot-rolled H-shapes has been proposed as one of the criteria for evaluating high-performance steel structures. Academics in China have proposed a built-up column comprising structural T-shapes and hot-rolled H-shapes. However, the market's low output of structural T-shapes limits the technological applications of this built-up column. This study proposes a new T-shaped built-up columns column (NTBC) design in which the columns are connected using two hot-rolled H-shapes. Based on the test, the global buckling of the NTBC is numerically evaluated under an axial compression load, and the findings are compared with the present national design specifications in line with the comprehensive defects suggested by the Chinese design standard GB 50017. The global buckling mode of NTBCs is identical to that of the classic welded T-shaped column, according to a comparison of 72 specimens of Q345 and Q460 steel. Local buckling is not evident. Finally, through data comparison and reliability analysis, compression column curves that can be used for the global buckling design of NTBCs were recommended in the GB50017 and EN1993-1-1, respectively.