Quick Repair of Damaged Infill Walls with Externally Bonded FRPU Composites: Shake Table Tests

The paper presents the results of research on a nearly full-scale, 1-story reinforced-concrete (RC) spatial frame structure with masonry infill walls tested on a shake table. The experiment was conducted in four phases to investigate the in-plane and out-of-plane responses of the infill walls of the specimen. The use of a digital image correlation (DIC) technique with noncommercial analysis system allowed the computation of principal strains for the infill. Two methods of infill-RC frame protection using polyurethane resin (PU) flexible joints (PUFJ) at the RC frame-infill connection and an external innovative fiber-reinforced PU (FRPU) repair system were considered in the research. The test results indicated that the in-plane and out-of-plane infill performance was enhanced under seismic excitations. The PUFJs at the interface of the frame and infill walls helped the infills to withstand dynamic excitation of high intensity with repairable damage. Furthermore, the externally applied glass FRPU repair system efficiently protected the damaged masonry infills against collapse under out-of-plane excitation while restoring a significant portion of their in-plane stiffness. The variable contributions of the RC frame and of the brick infills when protected with innovative joints are evaluated through three-dimensional finite-element models. (C) 2022 AmericanSociety of Civil Engineers