Experimental tests on full scale frp/frcm confined masonry columns subjected to axial load

The results of an experimental program performed on full-scale masonry columns strengthened with different composite systems are provided in the present paper. The same kind of study has been previously performed by the authors on medium scale masonry columns, using the same materials for both the masonry core and for the FRP systems. Masonry was formed by prismatic block of calcareous stone and joints were made by using a lime/pozzolan based-mortar, with a thickness of 10 mm. The experimental program involved six full scale masonry columns with a square cross section having a side length of 40 cm, and 210 cm height. The following test schemes were studied: control unconfined columns; column with continuous wrapping by using unidirectional Glass FRP (GFRP) sheets; column with discontinuous wrapping by using GFRP unidirectional sheets; column with continuous GFRP wrapping and internal carbon FRP (CFRP) bars bonded in the transverse directions with an epoxy resin; column wrapped with continuous alkali resistant GFRP grid and steel spikes bonded together in lime based matrix. The experimental results are presented and discussed in the paper; failure modes, strength and ductility are discussed by comparing the different strengthening techniques that were tested. The results confirmed that FRP-confinement may be considered an effective technique able to increase the load-carrying capacity and at the same time the axial deformability of the compressed columns. A ductile behaviour was observed in confined columns as also expected from the previous results available for small and middle scale columns. A comparison between experimental data and theoretical predictions provided by the new analytical model found in the guidelines of the CNR-DT 200/2012 technical document is also illustrated.