Abstract
This paper describes a study on the extreme thick-walled cold-formed square columns which are manufactured from circular to square shape, of which the width was 800 mm and the thickness was 22 mm. A systematic investigation of material behavior, residual stress distribution, and axial compression performance was performed numerically and experimentally. Results demonstrate thefollowing.1) The material properties of cold-formed columns manufactured by indirect method are clearly changed because of the cold-formed processes and are more uniform than those of cold-formed columns manufactured by direct method. 2)The extreme thick-walled cold-formed square columns work well under axial compression. 3) The residual stresses at the middle and corner parts of extreme thick-walled cold-formed square columnsareapproximately95 and 210 MPa, respectively.
1. Introduction
Cold-formed steel members are widely used in civil engineering because of their high strength-to-weight ratio; their thickness is generally limited to approximately3 mm because of the limitations of coldforming technology in the early stage. This thickness is much thinner than that of hot-rolled steel section. Nowadays, cold-formed sections with a wall-thickness greater than 6 mm, which are referred to as “thick-walled”, are more commonly manufactured and used in civil engineering [1]. They are commonly fabricated as closed shapes, such as circular or square hollow sections, and used increasingly in columns of high-rise buildings. The maximum size for the square hollow section is 800 mm wide by 22 mm thick; this type of section was used in the Tianjin Wanhui Square Project in China.
6. Conclusion
Through the experimental research and numerical analysis of the axial compression behavior of the extremely thick-walled cold-formed square columns, the following conclusions were obtained:
1) The material properties of square cold-formed columns manufactured from circular hollow tube change clearly due to the cold-formed processes; their properties are more uniform than that of cold-formed columns manufactured by steel plates.
