Externally Bonded Reinforcement on Grooves Technique in Circular Reinforced Columns Strengthened with Longitudinal Carbon Fiber-Reinforced Polymer under Eccentric Loading

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Title: Externally Bonded Reinforcement on Grooves Technique in Circular Reinforced Columns Strengthened with Longitudinal Carbon Fiber-Reinforced Polymer under Eccentric Loading

Author(s): Ala Torabian and Davood Mostofinejad

Publication: Structural Journal

Volume: 114

Issue: 04

Appears on pages(s): 861-873

Keywords: buckling; carbon-fiber reinforced polymer composites; columns; eccentric loading; externally bonded reinforcement; externally bonded reinforcement on grooves (EBROG); grooving method; reinforced concrete

Date: 7/1/2017

Abstract:
The present study investigates the application of carbon-fiber reinforced polymer (CFRP) composites with longitudinally aligned fibers to enhance the load-carrying capacity of circular reinforced concrete (RC) columns under eccentric loading. In such columns, the longitudinal fiber-reinforced polymer (FRP) composites subjected to compression generally buckle and lose their resistance; thus, they naturally fail to contribute to column strength. In this study, a recently introduced strengthening method called the “grooving method” (GM) is employed as a technique, “externally bonded reinforcement on grooves” (EBROG), to postpone the buckling of FRP sheets. The results are then compared with those of the conventional externally bonded reinforcement (EBR) method. For this purpose, 35 cylindrical RC specimens, each 150 mm (5.91 in.) in diameter and 500 mm (19.69 in.) in height, are subjected to both the compression test with different eccentricities and the four-point flexural bending test representing infinite eccentricity. Experimental results indicate the significantly greater contribution of the EBROG technique, compared to the EBR, to postponing the buckling of FRP composites and to increasing the strength of the specimens. Theoretical calculations are also performed and the results are compared with experimental ones. The calculations indicate a good agreement between theoretical and experimental results, confirming the superiority of the EBROG over the EBR technique.