Micro-mechanical FE modelling and constitutive parameters calibration of masonry panels strengthened with CFRP sheets

This paper describes the development of a micro-mechanical Finite Element model apt to reproduce the behavior of masonry walls reinforced with Carbon Fiber Reinforced Polymer (CFRP) sheets, monotonically loaded by out of plane actions. According to the results of previous experimental programs carried out by the Authors, in the case of CFRP sheets bonded parallel to the bed joints, such walls behave like un-connected masonry portions (similar to strengthened masonry beams). For this reason, only such effective part was considered in both the experimental program (already published by the Authors) and the numerical simulations. Both simply bonded and anchored CFRP reinforcements have been considered in the paper. Particular attention was paid to the definition of the constitutive parameters, calibrated on the basis of several experimental campaigns previously performed by the Authors. Since fracture energy of bulk materials and adhesive tangential strength of the reinforcement are generally thought of as difficult to experimentally determine and can be affected by uncertainties, a sensitivity analysis concerning such parameters is described in the paper. The numerical predictions have been compared to the experimental outcomes in terms of load displacement diagrams, stress distribution and damage evolution; the proposed numerical model seems to well reproduce the general experimental behavior.