Seismic strengthening of partially grouted masonry walls with openings: Evaluation of ferrocement and BTRM solutions

This paper presents an experimental study on the seismic performance of partially grouted reinforced masonry (PG-RM) walls strengthened with two solutions: Ferrocement coating (welded wire steel mesh embedded in cementitious mortar, WWM) and Basalt Textile Reinforced Mortar (BTRM) layer. For this purpose, two full-scale walls were built with hollow concrete units, with identical geometry and construction details of a previously reported tested wall, which acts as the control specimen (unstrengthened case) in this study. The walls, with a window-type opening and another door-type opening, were strengthened on one of their sides and tested under the combined action of constant axial compression and cyclic lateral loading up to failure. The experimental results show that both strengthening solutions increased the investigated walls' initial stiffness and lateral capacity. The increase in lateral capacity of both solutions was similar, about 37%. The 2D-DIC analysis implemented during the tests was instrumental in highlighting the areas on the strengthened walls where high strains were developed. The damage registered on the BTRM layer was more consistent with what was observed on the surface of the unstrengthened wall. Meanwhile, the damage reported on the wall strengthened with WWM did not exhibit apparent damage at higher drift levels due to the detachment between the ferrocement coating and the masonry substrate. Finally, the performance of some procedures to compute the contribution of the studied strengthening solutions was also assessed.