Numerical tool to predict the compressive capacity of squared masonry columns strengthened with FRP jackets

A numerical tool for the strength prediction of squared columns made of periodic masonry and strengthened with FRP jackets is presented. The formulation is based on an incremental plasticity theory that rely on equilibrium, compatibility, and kinematic equations. The strength domain of brick units and mortar joints is bounded by a multi-surface yield criteria: Mohr-Coulomb criteria in shear, a compression cap and a Rankine tension cut-off. The FRP failure is modelled according to a maximum tensile strength. A brittle response is considered for the system constituents, with exception for brick units and mortar joints in which an elasto-plastic response with limited ductility is assumed. The results of the proposed model were validated with the experimental data, and also compared with the ones retrieved from existing literature approaches and code-based formulas. Promising results are found and the model is fast since provides solutions in few strain increments.