A Numerical Comparison between Spiral Transverse RC and CFST Columns under Loads of Varying Eccentricities

This paper is the first to present the results of a numerical comparison between the performances of two newly developed concrete columns namely: multi-tied spiral transverse reinforced (MTSTR) column and concrete-filled steel tube (CFST) column under eccentric compressive loads. The behavior of MTSTR columns under eccentric loads has not been studied until today and also this behavior is not compared to that of the CFST columns. The numerical models of these columns were constructed using the nonlinear finite element method and validated against the previously published experimental data in the literature. Concrete damage plasticity model and elastic-perfect plastic model were used to simulate the behavior of concrete core and steel of the columns, respectively. This provides the capability of modeling of the nonlinear large deformations of the columns. The obtained results show that the MTSTR columns can provide greater load carrying capacity, ductility, and energy absorption with slightly lower initial stiffness than the CFST columns under the same eccentricities. For instance, the load-carrying capacity of MTSTR column is 18 percent greater than that of the CFST column when the load eccentricity is 100 mm. In case of 100 mm eccentricity, the ductility of the improved version of the MTSTR column proposed in this study is 30 percent greater than CFST one.