Improving Seismic Performance of Masonry Structures with Openings by Polypropylene Bands and L-Shaped Reinforcing Bars

A previous study using a scaled-down model of single-room masonry structures tested on a shaking table has shown that strength may be considerably increased by tying up the masonry walls by polypropylene (PP) bands, wrapping the walls using steel wire mesh, and providing horizontal L-shaped reinforcing bars at corners. The effectiveness of the same economic approaches and their combinations has been studied for similar scaled-down models with proportionate openings representing doors and windows, as a logical further scope of the previous study testing these models on a shaking table. As the presence of openings influences the crack and damage propagation leading to failure, the present study may give a more realistic picture of the seismic behavior of masonry structures with openings. Experiments have shown that PP bands were more effective than horizontal L-shaped reinforcing bars in arresting cracks and preventing collapse of the models, even those severely damaged. Further, the most important aspect of the study is that the technique is economical and can be implemented without involvement of any technical manpower or sophisticated equipment. The interesting observations regarding the effectiveness of such economical strengthening measures obtained from the study may be helpful for seismic strengthening of real-life masonry structures with door and window openings, leading to broad guidelines in this direction.