Seismic retrofitting of R/C columns having plain rebars using CFRP sheets for improved strength and ductility

This experimental work focuses on the retrofitting of reinforced concrete columns using carbon fiber reinforced polymer (CFRP) sheets to improve their strength and ductility capacities. Plain rebars, inadequate splicing lengths and insufficient stirrup spacing were the main parameters to reflect the old construction practice. The effectiveness of CFRP strengthening technique was studied. The test results showed that retrofitting with CFRP sheets was effective for columns with continuous rebars. However, only a slight improvement in performance was obtained for the retrofitted lap-spliced column. When the column was retrofitted by welding of dowel rebars with longitudinal rebars near splicing region and then wrapped with CFRP sheets, its strength, ductility and energy dissipation capacity improved significantly.