A Simplified Modelling Approach for the In-Plane Analysis of Masonry Structures Strengthened by FRCMs

Among the many strengthening techniques introduced for the seismic retrofitting of the masonry structures, FRCM strategies, based on the application of fibre-reinforced composite materials on the masonry surface through inorganic mortar layers, has become object of research due to their good performances in terms of physic and mechanic compatibility with historical substrate, low invasiveness and capacity to improve both the in-plane and the out of plane masonry behaviour increasing the capacity and the ductility of the structure. In this paper, a simplified discrete model is proposed to simulate the in-plane behaviour of masonry panels strengthened by FRCM systems. The proposed modelling approach is based on the DMEM model, whose numerical configuration can adapt to encompass the properties of the externally bonded strengthening system. According to the proposed strategy, the masonry support and the FRCM layers are simulated by an equivalent homogeneous material, discretized by a mesh of shear-deformable articulated quadrilaterals interacting along their edges by means of cohesive-friction links. The model is implemented in OpenSees and validated by simulating experimental shear-diagonal tests, available in literature.