1. The document reviews research on steel-concrete composite columns, where steel columns are infilled with concrete. Wire mesh is welded inside steel columns to improve bond between steel and concrete.
2. Three composite columns and three reinforced concrete columns of the same size were tested and compared. The composite columns showed better structural behavior than reinforced concrete columns in terms of ultimate strength, ductility, energy absorption capacity, and stiffness.
3. The literature review discussed previous research on composite columns that found infilling concrete inside steel tubes improves tensile strength and load capacity compared to hollow steel tubes. Previous studies also showed that composite columns experienced less damage than steel-only columns under the same loads.