Numerical Simulation of Behavior of Spirally Reinforced Columns

From experimental studies, the strength of concrete columns is known to be enhanced by lateral reinforcement. The quantitative correlation of the strength and the lateral reinforcement configuration remains difficult. In this paper, a nonlinear finite element procedure is developed to simulate the behavior of centrally loaded spirally reinforced circular columns. The concrete is characterized by a carefully calibrated nonlinear material model, which is coupled with a smearedcrack model to cover both compression and tension stress states. The accuracy of the finite element simulation is established through comparisons with experimental results. A parametric study is then carried out to study the confining mechanism and to generate data for actual‐size columns. It is found that the confining stress at the core of the column correlates well with an approximated formula used to develop strength formulas. The existing strength formulas, however, tend to overestimate the strength of columns with heavy spiral reinforcement. Based on the combined experimental and numerical simulation data, a new empirical strength formula is suggested.