ACI 440.2R Design Approach for the Strength and Axial Capacity of Columns Made of CFFT

Any Numerous experimental studies have been conducted on specimens consisting of concrete-Cast in Place FRP tubes, resulting in various models for predicting their compressive strengths. The advantages of FRP tubes include confinement, serving as jackets, providing shear and flexural resistance, and acting as permanent formwork. This paper presents both experimental test outcomes and a theoretical examination involving twelve cylinders and eleven columns made of concrete-filled FRP tubes (CFFT). The parameters considered in the investigation encompass confinement through glass (GFRP) tubes, the impact of laminate thickness in GFRP tubes, and the presence of longitudinal steel bars. The investigation involves a comparison between experimental test results and theoretical predictions based on the ACI 440.2R-17 design guidelines, focusing on confined strength and ultimate carrying capacity. The findings suggest that the design equations from ACI 440.2R-17 tend to overestimate the factored axial load capacity of short CFFT columns when compared to loads at different levels.