The vulnerability of unreinforced masonry buildings (URM) to moderate groun
d motions is a fact recognized by the earthquake engineering commonly. In t
his paper, an innovative retrofitting system for URM buildings using glass
fiber reinforced polymer (GFRP) strips is investigated. The experimental re
sults for four retrofitted URM walls subjected to cyclic out-of-plane loadi
ng are presented herein. The first three specimens were constructed in sing
le wythe, and the fourth one in double wythe. The height-thickness ratio fo
r 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 a
nd defect up to 1 /20 times the wall height. Strength and deformation capac
ity of the walls were significantly improved by the investigated retrofitti
ng technique.