Seismic response of PP-band and FRP retrofitted house models under shake table testing

Abstract Current research work presents the seismic response of brick masonry houses retrofitted by different composite materials under dynamic shake table tests. Tests were performed on 1:4 scaled unreinforced masonry (URM), Polypropylene (PP-band) retrofitted, Glass Fiber Reinforced Polymer (FRP) retrofitted and FRP + PP-band retrofitted house models. A minimum reinforcement ratio of FRP was selected to use with PP-band as FRP + PP-band composite. Results show that URM is highly brittle and can hardly withstand an ordinary ground motion, whereas PP-band retrofitting has increased the ability of URM houses to withstand a severe ground motion with intense cracking and separation of wall segments. However, despite no collapses, PP-band retrofitted house model had lost its serviceability when subjected to strong input ground motion. Unlike PP-band, FRP retrofitted houses were collapsed suddenly without giving any warning with respect to ductility and energy dissipation. The sudden failure of FRP houses is attributed to very low FRP reinforcement ratio (0.0006), as it is an expensive material and its sole use in higher amounts would result in significant increase of retrofitting costs. Results show that a potential use of FRP in combination with PP-band is a good alternative as it significantly enhances the shear capacity, energy dissipation as well as the ductility of URM masonry structure at a very low retrofitting costs.