Shake Table Tests on FRP-Rehabilitated RC Shear Walls

Abstract

This paper investigates the behavior of two 8-story cantilevered RC shear walls rehabilitated using carbon fiber-reinforced polymer (CFRP) composite sheets when subjected to base excitations from a shake table. The two original reduced size walls (1:0.429) were tested on the shake table of École Polytechnique de Montréal to investigate the effect of higher modes of vibration on the behavior of multistory RC walls. The walls were subjected to several levels of ground motion excitation that matches the design spectrum of Montréal city in Québec, Canada. The original walls showed significant inelastic deformations at the 6th-story level in addition to those at the base plastic hinge. After the shake table tests on each of the two original walls, the damaged walls were rehabilitated and resubjected to the same levels of the ground motion excitations. This paper focuses on the FRP-rehabilitation of the original walls. The rehabilitation scheme for the two walls aimed to increase the flexural and shear capacities of the wall at the 6th-story panel because of the observed increase in demand at that level, whereas the base panel was confined using CFRP sheets to increase the ductility capacity without increasing strength. The rehabilitated walls showed satisfactory performance with improved flexural strength at the 6th-story panel. The rehabilitation scheme resulted in a reduced wall rotation and lower strain values of the flexural steel rebars at the 6th-story panel. The shear demands and bending moments on the FRP-rehabilitated walls were higher than those of the original ones.