A COMPARATIVE STUDY OF COST AND RESISTANCE BETWEEN TUBULAR STEEL COLUMNS AND CONCRETE-FILLED TUBULAR STEEL COLUMNS

Resumo

The use of steel-concrete composite structures is not a recent trend in construction; however,
it has significantly increased after the 1960s. The quest for streamlining construction processes
encouraged the employment of steel and steel-concrete composite structures. Both structural systems
provide reductions in cost with labor and materials, as well as increased dimensional precision, structural
efficiency and cleaner construction sites. In this context, the use of steel-concrete composite columns is
commonly observed, and these may present themselves as steel tubular sections, filled with concrete.
Such sections provide an increase in compressive strength due to concrete confinement within the steel
tube and eliminate the need for form-work and steel reinforcement during construction. Circular steel
sections are more efficient to bear torsional forces, and present good behavior when subjected to
combined actions. This study analyzes the main criteria and concepts for the design of composite
columns with concrete-filled circular hollow sections and steel circular hollow sections according to the
Brazilian standards ABNT NBR 8800 and ABNT NBR 16239, under compression and combined
bending. A cost comparison between the two aforementioned types of column was obtained by means
of an algorithm developed with Visual Basic for Applications, considering equivalent resistances and
the prices applied in Brazil’s Southeast region. As an additional analysis, the effect of the confined
concrete on the overall mechanical resistance of the columns was also evaluated.