Influence of Aspect Ratio and Corner Radius on the Structural Performance of Rectangular Columns with UHPFRC Jacketing

Abstract This study presents an investigation on the effect of concrete columns cross sectional properties on the performance of Ultra High-Performance Fibre Reinforced Concrete (UHPFRC) jacket. This research explores the potential of UHPFRC as a novel and cost-effective material for rehabilitating damaged concrete structures, particularly focusing on its effectiveness in strengthening square and rectangular columns, where existing methods such as Steel Fibre Reinforced Polymer (FRP) have shown limitations. For that purpose, the cross sectional properties are namely aspect ratio, and corner to radius ratio. A total of 36 reinforced concrete column specimens were cast with varied size ratio. The jacketing cementitious UHPFRC material is 20 mm thick and made of UHPFRC. Two column specimens for each property were subjected to axial compression load. The performances of concrete column were measured in terms of maximum load carrying capacity, stiffness, ductility, and toughness. The results demonstrate that UHPFRC jacketing significantly enhances the load-carrying capacity of rectangular columns, with increases of 44%, 33%, and 31% for aspect ratios of 1.25, 1.50, and 1.75, respectively. The combined effect of UHPFRC jacketing and corner radius modifications led to an overall increase of up to 85%, 63%, and 53% in load-carrying capacity for the respective aspect ratios, highlighting the synergistic benefits of these interventions in improving structural performance.