نوع مقاله : علمی - پژوهشی
عنوان مقاله English
نویسنده English
Concrete-filled steel tubular (CFST) columns are widely used in modern structures due to their high load-carrying capacity, adequate ductility, and favorable performance under compressive loading. Among them, concrete-filled double-skin steel tubular (CFDST) columns, owing to the presence of two steel tubes and a concrete core, exhibit greater confinement capability and structural stability compared with conventional columns. However, under high loading levels, local buckling of the steel tubes may occur, leading to a reduction in the effectiveness of concrete confinement. Therefore, the use of external stiffening elements can play a significant role in enhancing the behavior of such columns. In this study, the effect of transverse stiffeners in the form of helical springs on the axial compressive behavior of CFDST columns is investigated using numerical modeling in ABAQUS. The influence of two main parameters, namely the pitch and diameter of the helical spring, on the structural response of the columns is examined through 11 numerical models.The results indicate that the use of helical springs leads to a significant increase in load-carrying capacity and an improvement in the axial performance of CFDST columns. Reducing the spring pitch enhances concrete confinement and improves stress distribution in the steel tubes, and in the best case, an increase of about 66% in load capacity compared with the unstrengthened model is observed. Moreover, increasing the spring diameter leads to higher lateral stiffness and reduced radial deformations, which in turn results in an increase in the load-carrying capacity of the column. The findings of this research demonstrate that employing helical springs as external stiffeners can be an effective strategy for improving the structural performance of composite steel–concrete columns.
کلیدواژهها English