Experimental and Numerical Studies on Effectiveness of Hybrid FRP Strengthening on Behavior of RC Columns under High Eccentric Compression

Abstract

This paper discusses the efficacy of different fiber-reinforced polymer (FRP) techniques on the behavior of RC columns under uniaxial high eccentric compression. Eight RC columns were strengthened using three FRP strengthening schemes: (1) near surface mounting (NSM), (2) external bonding (EB), and (3) hybrid strengthening, which uses a combination of NSM and EB. All the columns were tested under an eccentricity (e) to column depth (h) ratio of 0.63. The results obtained from the experiments were compared with the results of numerical analysis using the finite-element (FE) software developed at the University of Stuttgart. The hybrid FRP-strengthened specimens showed better performance compared with only NSM or EB in enhancing the peak strength and ductility by 51% and 277%, respectively, when compared with the control RC columns. Moreover, the brittle bond failure typically observed in NSM-strengthened columns was effectively prevented through FRP confinement in hybrid strengthening. The FE modeling approach developed in this work effectively captured the overall behavior of RC columns under eccentric compression. An extensive parametric analysis using the validated modeling approach was performed to quantify the effectiveness of the different strengthening techniques for a wider range of design parameters.