Comparison of Composite, Steel and Reinforced Concrete Columns

Architects now often require the use of slender load-bearing structures, but they must be sufficiently resistant to all loads. The use of the composite steel-concrete columns joins the main advantages of the individual materials. The most commonly used composite is the steel-concrete. Depending on the amount, shape, location and utilization rate of the steel or concrete, the composite columns are closer to the steel or reinforced concrete columns. The composite steel-concrete structures utilize high compressive strength of concrete and high tensile resistance of the structural steel. The steel-concrete connection is therefore highly efficient, and by combining, it is possible to produce relatively lightweight structures with wide use in high-rise buildings and bridges. The composite steel-concrete columns have high strength with a relatively small cross-sectional area. Composite efficiency also depends on the type of composite steel-concrete column. The most commonly used type is a steel tube filled with concrete. In the case of a steel tube filled with concrete, it is possible to use the confining effect of a steel tube, which prevents lateral deformation of the concrete and at the same time, the concrete core prevents compression of the steel tube. These two effects increase the total resistance of the composite steel-concrete column. Other types are partially or fully concrete-encased steel section. The use of a fully concrete-encased steel cross-section increases the fire resistance of the cross-section as the steel profile is protected by concrete against the effects of fire. The criterion for selecting the appropriate shape and type of the steel part of the column cross-section, the design of the global structural system of the object should be taken into account. Not only one European standard is needed to design composite steel-concrete structures. In addition to the standard EN 1994-1-1 Design of composite steel and concrete structures, it is also necessary to use standards EN 1992-1-1 Design of concrete structures and EN 1993-1-1 Design of steel structures.