The role of spandrels within masonry walls with openings: an experimental investigation

Quasi-static lateral loading tests were carried out on a full-scale masonry wall with an opening to assess the contribution of spandrels to the in-plane nonlinear behaviour of masonry walls. The wall response was first assessed through a monotonic test up to the attainment of moderate cracking in the spandrel. Second, the pre-damaged wall was cyclically tested up to about the same lateral drift reached in the monotonic test. Finally, the wall was repaired and upgraded through inorganic matrix-grid (IMG) composites applied to the spandrel. A cyclic test was then performed up to a near-collapse state. In this paper the experimental results are discussed with special emphasis to parameters that quantify the in-plane nonlinear response. In all tests the piers provided high displacement capacity through a rocking response. Both the load-carrying capacity and the post-peak strength degradation were affected by nonlinear behaviour of the spandrel panel. The IMG strengthening system provided high energy dissipation capacity to the spandrel panel, restoring the load-carrying capacity of the as-built wall, and delaying strength degradation at larger drifts. Low residual displacements and full reversibility could make the IMG strengthening system attractive for historic buildings.