Experimental research in the field of masonry constructions is typically consisted in: quasi-static tests on individual panels subjected to predefined boundary conditions; and quasi-static, pseudo-dynamic or shaking table tests on building prototypes.

In order to assess the contribution of spandrels to the in-plane non-linear behaviour of masonry walls with openings, three quasi-static tests were carried out on a full-scale masonry wall composed by two piers and a spandrel panel. Those tests consisted in the application of constant vertical forces to the piers and a displacement-controlled horizontal force to the spandrel. The experimental setup allowed to avoid predefined boundary conditions on the spandrel panel and to assess its interaction with adjoining piers.

The wall was first subjected to monotonically-increasing displacements until a moderate damage was detected on the spandrel panel. The wall was cyclically tested up to almost the same lateral drift reached during monotonic test, in order to preliminarily investigate the effects of previous damage on the non-linear response. The wall was then repaired by replacing some damaged stones and filling cracks, while the spandrel was upgraded with inorganic matrix-grid (IMG) composites. Finally, a cyclic lateral-loading test was carried out on the IMG-strengthened wall up to a near-collapse state.

This paper illustrates the procedures and instrumentations employed for such tests, the observed damage and the main experimental results. Most of damage developed in the spandrel panel affecting both lateral load-carrying capacity and strength degradation of the wall. Rocking of piers induced a hysteretic behaviour characterised by small residual displacements and re-centring capacity. The IMG strengthening system was able to provide significant energy dissipation capacity to the spandrel panel, restoring the load-bearing capacity of the as-built wall, and delaying strength degradation at larger drift levels. Displacement ductility, overstrength and strength reduction factor of the three tested models are also discussed.