Experimental and Field Performance of PP Band–Retrofitted Masonry: Evaluation of Seismic Behavior

Unreinforced masonry (URM) buildings exhibited extreme vulnerability during past earthquakes, although these are shelters for a majority population in many earthquake-prone developing countries. Most of the current retrofitting techniques used for such structures are either expensive or require highly skilled labor or sophisticated equipment for implementation. On the other hand, the retrofitting technique proposed in this paper is economical and easy to apply. This paper aims at examining the performance of the retrofitting technique using polypropylene (PP) band. The displacement-controlled lateral deformation has been investigated experimentally. The monotonic load-displacement behaviors of a URM wall and the wall retrofitted with PP band are compared. It was found that the URM wall retrofitted by PP band improves the ductility and energy absorption capacity by three and two times, respectively. Performance of a full-scale masonry building retrofitted with PP band in Nepal during the last Gorkha earthquake of April 25, 2015, has also been presented in this paper. It was observed that the PP band–retrofitted masonry building survived, whereas many nearby buildings experienced severe damage and some of them collapsed. This study demonstrates the efficacy and practicability of use of PP band for improving seismic resistance of a URM structure.