Out-of-plane behavior of brick masonry walls strengthened with fiber composites

The vulnerability of unreinforced masonry buildings (URM) to moderate ground motions is a fact recognized by the earthquake engineering community. In this paper, an innovative retrofitting system for URM buildings using glass fiber reinforced polymer (GFRP) strips is investigated. The experimental results for four retrofitted URM walls subjected to cyclic out-of-plane loading are presented herein. The first three specimens were constructed in single wythe, and the fourth one in double wythe. The height-thickness ratio for all specimens was 28. Depending on the reinforcement ratio, single wythe walls failed in tension, excessive delamination, or a combination of both. Failure modes in the double wythe wall were peeling off of composite strips and splitting of the wythes. From experimental results, it was found that walls were capable of supporting pressures of up to 25 times their weight and deflect up to 1/20 times the wall height. Strength and deformation capacity of the walls were significantly improved by the investigated retrofitting technique.