Effect of Inner Steel Tube Cross-Sectional Shape on Compressive Behavior of Square FRP-Concrete-Steel Double-Skin Tubular Columns

摘要

Recently, a new type of composite system was proposed in the form of fibre reinforced polymer (FRP)-concrete-steel double-skin tubular columns (DSTCs). The performance of this column system, which consists of an outer tube made of FRP and an inner tube made of steel, has been experimentally investigated in a number of studies. However, apart from a single study reported on square DSTCs, all of the existing studies have been concerned with DSTCs with circular external tubes. This paper reports on part of an ongoing experimental program at the University of Adelaide that was aimed at addressing this research gap. The effect of crosssectional shape of inner steel tube on compressive behaviour of square DSTCs was investigated through the test of 16 hollow and concrete-filled DSTCs. The result of the experimental study indicate that concrete in hollow DSTCs with circular inner steel tubes develop significantly larger ultimate axial stresses and strains than concrete in companion hollow DSTCs with square inner steel tubes. On the other hand, the results also indicate that the presence of a concrete-filling inside inner steel tubes results in a significant improvement in the behavior of DSTCs with square inner steel tubes.