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 sys-tem 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, sin-gle wythe walls failed in tension, excessive delamination, or a com-bination of both. Failure modes in the double wythe wall were peel-ing off of composite strips and splitting of the wythes. From exper-imental 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.