Seismic performance of stiffened steel box column with different corner stiffener arrangements: a numerical approach

The purpose of this study is to investigate a stiffening method with numerical analysis to improve the performance of hollow steel box columns, which are commonly and widely used in highway bridges. The major issue with the hollow steel column is local and global buckling at the base under different loadings. There are several methods to prevent local buckling and also to enhance the strength and ductility of the hollow column. Here, the performance of the steel column is improved by adding longitudinal (vertical and corner) and transverse stiffeners inside the column. In this research, the stiffened steel columns are numerically analysed by finite element method incorporating material and geometric non-linearities under constant axial and lateral cyclic loadings. From three different hardening models, the combined hardening material model is used for the steel material for the numerical analysis based on performance. The analytical results clearly show that the strength is improved by stiffening the column in the middle of the plates using vertical stiffeners, and the ductility is improved by stiffening the column at the corners using corner plates. The corner stiffeners avoid faster degradation of strength and also increase the lateral load-carrying capacity at maximum displacement level. It is clear from the numerical results that the overall performance of the hollow steel column is improved with vertical and corner stiffeners.