Strain compatibility method for the design of short rectangular concrete-filled tube columns under eccentric axial loads

Given that there are few concrete stress-strain models available for rectangular CFT sections with high-strength materials, this study attempts to develop an empirical and practical stress-strain model that can be used in conjunction with the strain compatibility method of the American Concrete Institute Code (ACI 318-14), American Institute of Steel Construction Specification (AISC 360-10), and Eurocode 4. For a better understanding, the structural provisions of rectangular CFT columns in ACI 318-14, AISC 360-10 and Eurocode 4 are comparatively reviewed. Then, an updated database is assembled from previous and recent test results of rectangular CFT columns subjected to eccentric axial loads to evaluate whether the existing provisions and/or stress-strain models for concrete can be used. Finally, a new concrete stress-strain model is proposed that leads to more accurate and more consistent prediction of the P-M interaction strength of rectangular CFT columns under general design conditions.