(1) Ass. Professor, Struct. Section of DACS , University Politecnica of Marche, Italy
(2) PhD Student, University Politecnica of Marche, Italy

Un-reinforced masonry structures (URM) are not considered to be resistant enough to earthquakes, although many masonry buildings have borne seismic action effects without any damage.
Among those which have failed, the most frequent cause of damage was due to shear. Composite materials (FRP) supply the required tensile strength that may ensure an adequate value of ductility to the masonry walls during earthquakes.
The aim of this paper is to analyse and compare the shear behaviour of masonry T-shape cross walls without strengthening under combined compression, shear loading and damaged by flexural failure mode with strengthened walls. Three experimental masonry models in ½ scale clay blocks, un-strengthened and strengthened by CFRP have been tested in the laboratory. A comparison of experimental data with theoretical results obtained by FE modelling and an analytical simplified truss-tie model is shown and discussed.