Fiber-Reinforced Polymer-Confined Non-Circular Columns with Shape Modification: A Comprehensive Review

The implementation of shape modification (SM) to reinforced concrete (RC) columns has been demonstrated to be effective when enhancing the effectiveness of the fiber-reinforced polymer (FRP) confinement of the columns, particularly for non-circular columns. The SM approach generally includes modifying a square section into a circular one, modifying a rectangular section into an elliptical/oval one and modifying a square/rectangular section into a curvilinearized square/rectangular section. In this paper, a state-of-the-art review of studies on FRP-confined non-circular columns with SM is conducted. The effects of key parameters on the effectiveness of FRP confinement are discussed, and different methods for the implementation of SM in real applications are briefly introduced. The findings of the review further confirm the effectiveness of the SM approach, and the test results demonstrate the effectiveness and advantages of section curvilinearization with a limited increase in cross-sectional area. Additionally, existing theoretical models for FRP-confined concrete in columns with SM are summarized. Further research opportunities associated with FRP-confined non-circular columns with SM are identified.