Development of a Prototype System for Active Reinforcement of Concrete Columns with CFRP
摘要
This study presents the design, implementation, and evaluation of an innovative prototype system for actively confining concrete columns using Carbon Fiber Reinforced Polymer (CFRP) sheets. Recognizing the limitations of passive confinement methods—such as suboptimal utilization of CFRP properties, this research introduces a low-cost, scalable device that enables controlled prestressing of carbon fibers prior to bonding them to cylindrical concrete specimens. The prototype uses a steel-profile structure, a tensioning screw mechanism, and a guided path based on mathematical modeling to ensure uniform confinement along the column’s surface. Three groups of specimens were tested: unconfined, passively confined, and actively confined. Compression tests revealed that actively confined specimens showed superior performance compared to both control and passively confined groups. Notably, actively confined cylinders surpassed the capacity of the hydraulic press, making it impossible to record full failure data—highlighting the significant strength improvements achieved. Early-age testing further confirmed the benefits of active confinement, including improved crack control and energy absorption. Although quantitative failure loads could not be obtained due to equipment limitations, observations align closely with recent experimental studies reporting compressive strength gains of 15–25% and ductility increases up to 30% when using prestressed CFRP. The proposed active confinement technique thus offers a practical and effective solution to enhance the structural capacity and resilience of concrete columns, with potential applications in both retrofit and new construction scenarios.