Double-leaf masonry walls under in-plane loading strengthened with GFRP/SRG strips

Abstract

Multiple-leaf masonry walls are usually adopted in historic buildings in seismic areas. An investigation on this type of masonry wall, characterised by two leaves of brickwork masonry and intermediate grout, has been carried out on models in laboratory. Knowing how historic masonry behaves under seismic action is fundamental for preserving architectural heritage. During earthquakes, masonry walls are subjected to shear loads that often lead to the ruin of an entire building. In recent years, the strengthening of masonry walls often foresees external bonded fibre reinforced polymers (FRPs) even if many aspects of this technique are not thoroughly known. In particular, the debonding mechanisms of FRP strips needs to be analysed using more experimental data.This paper presents the results of an investigation on historic unreinforced double-leaf masonry wall models built with historic solid clay bricks in scale 1/3rd. The unreinforced models were tested under combined compression and shear loading; after damage they were strengthened with two types of external bonded composite materials – diagonal Glass-FRP strips and steel fibre reinforced cement grout (SRG) – and then once again subjected to the same loading until failure. A comparison between the response of the unreinforced and reinforced model is presented, and the failure debonding mechanisms of strengthened shear wall models with GFRP/SRG strips are discussed.