Cyclic behavior of perforated masonry walls strengthened with glass fiber reinforced polymers

Many of the existing unreinforced masonry buildings are seismically vulnerable and require retrofitting. In this experimental study, the cyclic behavior of six, one-half scale, perforated unreinforced brick walls, before and after retrofitting, using Glass Fiber Reinforced Polymers (GFRPs), is investigated. The walls were built using one-half scale solid clay bricks and cement mortar to simulate the traditional walls built in Iran during the last 40 years of the 20th century. These walls had a window opening at their center. One brick wall was unreinforced and considered a reference specimen. Three walls were directly upgraded after construction using GFRPs. The fifth wall was first strengthened and tested. Then, the seismically damaged specimen was retrofitted, using GFRPs, and tested again. Each specimen was retrofitted on the surface of two sides. All specimens were tested under constant gravity load and incrementally increasing in-plane loading cycles. During the test, each wall was allowed to displace in its own plane. The key parameter was the strengthening configuration including the cross layout, grid layout, and combined layout. Strengthening by means of GFRPs significantly improved the strength, deformation capacity, and energy absorption of the brick wall. The increase in performance parameters was dependent upon GFRP layout.