Experimental and numerical investigation on cyclic behavior of masonry infilled RC frames retrofitted with partially bonded CFRP strips

Abstract

This paper investigates experimentally and numerically the behaviors of retrofitted masonry infilled reinforced concrete (RC) frames using totally bonded or partially bonded diagonal carbon fiber reinforced polymers (CFRP) strips under cyclic loads. Five 1/2-scaled, one bay, one storey nonductile RC frames were built and tested as bare and infilled reference specimens, and as x-cross CFRP sheets retrofitted specimens. Retrofitting the RC frames was based on the use of two different techniques; (a) totally bonded CFRP strips (b) partially bonded CFRP strips. Significant findings were noted while comparing the retrofitted specimens with reference specimens in terms of inter-storey drift, lateral load capacity, energy dissipation capacity, stiffness, and the observed damages. Moreover, using CFRP anchors delayed the debonding failure mode. A two-dimensional (2D) finite element model (FEM) of the tested frames was also developed to predict the behaviors of these specimens under cyclic loading. Element types and materials constitutive model of cyclic behavior were described. The infill-frame interaction, in addition to the interactions between CFRP and RC frames, were accurately mimicked. The suggested (2D) FEM was compared with experimental test results. Results of the FEM showed good agreement with test results, showing high accuracy in relation to ultimate load capacities and modes of failure. Bonded and partially bonded CFRP stripes showed similar lateral strength and stiffness.