Abstract
The behaviour of heritage masonry elements made of lime mortar and fired clay bricks is examined in this study, with focus on seismic strengthening using textile reinforced mortar overlays. An experimental investigation is described, which includes pairs of strengthened and non-strengthened diagonal compression tests on square panels as well as large-scale walls subjected to combined gravity and lateral cyclic loads. The diagonal panel tests show that the effectiveness of the strengthening depends in a non-proportional manner on the number of overlays, render thickness, and substrate strength. The enhancement in shear strength, using one to four mesh layers on each side, is shown to reach over five-folds, depending on a number of material and geometric parameters, with similar benefits in terms of stiffness and ductility. It is also shown that strut crushing typically governs the response of low-strength heritage masonry elements confined by textile reinforced mortar overlays. The tests on the relatively large walls, subjected to realistic gravity and lateral cyclic loading conditions also demonstrate the effectiveness of the strengthening approach where, depending on the mode of behaviour, the response can be shifted from a brittle failure to a relatively more ductile ultimate mechanism after strengthening. The findings provide essential information that is needed for detailed numerical and analytical studies towards the quantification of key inelastic response parameters of strengthened and non-strengthened heritage masonry for use in assessment and rehabilitation applications.