Axial Cyclic Behavior of RC Columns Strengthened with Longitudinal CFRP Sheets

The present study investigates the application of carbon-fiber reinforced polymer (CFRP) composites with longitudinally aligned fibers for enhancing the load carrying capacity and ductility of square reinforced concrete (RC) columns under cyclic axial compression. Global buckling of the composite described may result in the debonding of FRP off the column surface, which hinders to a considerable extent enhancements in the load carrying capacity and ductility of the strengthened columns. To limit the global buckling of the composite under compression, the recently developed externally bonded reinforcement in grooves (EBROG) was utilized in the present study and compared with the externally bonded reinforcement (EBR) method using the conventional surface preparation method. For this objective, 3 square RC columns, each with a cross section of 150 × 150 mm and a height of 900 mm, were tested under cyclic axial compression. Two strengthening techniques, EBR and EBROG, were used. Experimental results indicated the significantly greater contribution of the EBROG method, compared to that of the conventional EBR, to postponing the buckling of FRP composites and to increasing the load carrying capacity and ductility of the specimens.

Keywords:

CFRP , RC column , EBR , EBROG , Cyclic axial compressive loading