Numerical Investigation of Behavior of Steel-Reinforced Concrete Columns with Cruciform Steel Core under Eccentric Loading

Steel reinforced concrete (SRC) columns have become very popular in recent years due to their many advantages. In this study, to investigate the behavior of SRC columns with a cruciform steel section at their core, the ductility index and factors affecting it were investigated. Also, by calculating the necessary equations based on the plastic stress distribution method, a simple and practical method for designing these columns was provided. Accordingly, a finite element model was created using ABAQUS software for numerical study and was then validated with the results of a previous experimental study. A total of 16 columns with cruciform steel cores were analyzed for the present study. The effect of variables such as steel core percentage, concrete compressive strength, stirrup spacing, slenderness ratio, and load eccentricity ratio on the ductility index of these columns was discussed. The results showed that with increasing the eccentricity ratio, the bearing capacity decreases but the ductility index increases due to the change in behavior from compressive to flexural, such that as the eccentricity ratio increased from 0.1 to 0.4, the bearing capacity decreased by 59.1% but the ductility index increased by 28.2%.