Experimental analysis of historic masonry walls reinforced by CFRP under in-plane cyclic loading

Abstract

External bonding of Fiber Reinforced Polymers (FRPs) has become a popular technique for strengthening historic masonry wall buildings in seismic area. Although FRPs seem to improve response of historic masonry walls under in-plane shear loading, further investigations must specify a number of aspects for both researchers and practitioners. This paper presents an experimental analysis pertaining to the response of unreinforced and reinforced historic masonry walls built using full clay bricks in scale 1/3rd. On the basis of previous experimental research carried out by shear tests on triplets and unreinforced walls, a shear criterion for historic unreinforced masonry (HURM) has been assumed. In this experimental analysis two HURM walls, characterized by double T shape, were subjected to in-plane cyclic loading to shear cracking. The damaged walls were reinforced using horizontal–vertical and diagonal Carbon FRP strips. An anchorage system was also put into place to improve the adhesion of the strips used; the historic reinforced masonry (HRM) walls were tested by cyclic loading until failure. The experimental results are illustrated and discussed taking into account the delamination failure of the CFRP strips. Finally, the increase obtained in walls’ shear capacity is analysed considering theoretical bilinear diagrams and the coefficient of ductility.