Simple model for the nonlinear behavior of masonry arches reinforced with BTRM

The paper presents an easy-to-use nonlinear FE modelling for an insight into arches made by masonry strengthened with BTRM, which can be used by inexperienced users. Non-linearities are concentrated in the reinforcement and in the mortar joint, both modeled with elastic perfectly fragile truss elements (cutoff bars). Bricks, instead, are meshed with 4-node elastic elements. The goal is to evaluate the increase in the load-bearing capacity of arches reinforced with BTRM, also considering the contribution provided by the presence of anchor spikes. The reinforcement is modeled with elastic perfectly brittle cutoff bars directly connected to extrados nodes of the arch. Such cutoff bars are simply calibrated with standard coupon tests for which the maximum possible tension of the textile is considered. The mortar joint, on the other hand, is meshed with shear panels and cutoff bars (always elastic perfectly fragile) placed in a normal direction with respect to the joint to evaluate its behavior under pure Mode I. Necessary parameters to set mortar joints are easily obtainable from standard experimental tests, namely: elastic modulus, Poisson's ratio, and tensile strength. The model is tested on masonry arch tested in lab and reinforced with BTRM. The validation is obtained by comparing a series of numerical outcomes versus experimental data present available. Following a precise analysis of the global load-displacement curves and an evaluation of non-linearities that develop in the numerical model, the simplicity and robustness of the method presented is evaluated.