This paper presents an investigation on the efficiency of steel tubes in reinforcing self-compacting concrete (SCC) columns. A theoretical model is developed to study the axial behavior of SCC columns reinforced with steel tubes, considering the effects of confinement on the filled concrete by steel tubes and concrete core confined by spirals. The computational results are validated against the existing test results of SCC columns. The effects of various column parameters on the performance of SCC short columns under axial concentric loading are investigated. It is shown that the axial performance of SCC columns is influenced by the dimension and number of steel tubes, pitch of spirals, compressive strength of concrete, and yield stress of the steel tubes.
This paper investigates the structural performance of concrete-filled stainless steel tubular (CFSST) columns composed of rectangular and square sections. A fiber-based mathematical model is developed to simulate the nonlinear performance of such columns loaded concentrically accounting for the local buckling of steel tube. An accurate lateral pressure model, as well as a strength degradation parameter are proposed based on the existing test results and incorporated in the mathematical modeling developed. A large test dataset is used to validate the accuracy of the numerical prediction. The mathematical model is employed to study the sensitivities of important column parameters on their axial behavior. The accuracy of the existing confinement model of rectangular CFST columns is evaluated in predicting the performance of CFSST short columns. Furthermore, the accuracy of the existing codified design models as well as and the simplified design model proposed in this study to quantify the
This article investigates the axial compressive performance of concrete-filled double steel tubular (CFDST) short columns composed of circular section loaded concentrically. An experimental program comprised of compression tests on short columns is carried out to examine their structural performance. Axial compression tests on conventional concrete-filled steel tubular (CFST) columns and double-skin concrete-filled steel tubular (DCFST) columns are also performed for comparison purposes. The test parameters include the diameter-to-thickness of the outer and inner steel tubes, concrete strength, and diameter ratio. The test results exhibit that CFDST short columns composed of the circular section have improved structural performance compared to its CFST and DCFST counterparts. A theoretical model is also presented to simulate the test ultimate strengths and load-axial strain relationships of CFDST columns. The existing design models proposed including the codified design specifications