Structural Behavior of Reinforced Concrete Columns Under Eccentric Loads Strengthened by Steel Jackets Filled With Normal and High-Strength Concrete

Reinforced concrete (RC) columns are essential structural components in buildings and infrastructure, providing vertical load support and stability. However, these columns can be degraded over time due to various factors, such as environmental exposure, seismic events, and increased loading demands. As a result, the need for effective and reliable column-strengthening techniques arises to ensure the safety, durability, and longevity of structures. The main objective of this study is to investigate how fully strengthening damaged columns affects load-bearing capacity and overall structural performance. Moreover, this study tested thirteen reinforced concrete columns during the experimental program. The original dimensions of these columns were 150 * 150 * 1200 mm. One specimen served as a control, while the remaining twelve underwent strengthening and enlarged to be (250 * 250 * 1200) mm. These specimens varied in stirrup spacing, reinforcing materials such as glass fiber and steel rebar, and different concrete’s compressive strengths. The results revealed that the load increasing ratio values were increased from 2.87 to 4.13 times of the reference specimen. The failure pattern was changed from brittle failure to ductile failure. Both stress-strain behavior and axial load deformation were enhanced. The ductility was increased from twice to six times the value of the reference specimen. On the other hand, the designed proposal was compared with standard codes (ECP 203-2020 and Eurocode 4). Strengthening RC columns using steel jackets and filling with various concrete’s compressive strengths enhanced their durability, stiffness, and performance under eccentric loads.