Performance of concrete columns actively strengthened with hoop confinement: A state-of-the-art review

When concrete columns are strengthened with hoop confinement, the reinforcement material will take effect earlier if they are prestressed, thereby improving the material utilization rate, strengthening effects, and avoiding stress hysteresis. This paper systematically reviews the latest research progress of actively confined concrete and introduces the active-confinement mechanism, single-material active confinement, active-passive combined confinement, and the theoretical computation model of actively confined concrete. In addition, this paper evaluates and analyzes the advantages and disadvantages of construction techniques, anchoring methods, and the confined effects of various actively confined methods. Based on the strengthening mechanism of hoop confinement, the improvement of mechanical properties of concrete columns using different active confinement methods is expounded in detail. In addition, the theoretical models of active confinement are comprehensively summarized and expressed in a unified computation process. This paper will benefit the practitioners and researchers who wish to comprehensively understand the technique of actively confined concrete columns, and contribute to their further in-depth research and application.