Simple Numerical Procedure for the Analysis of Masonry Arches Strengthened with SRG

A general and simple computational approach for the analysis of masonry arches reinforced with SRG (Steel Reinforced Grout), suitable for practical application, is presented. Nonlinearities lump within the mortar joint and at the interface between support and SRG, represented by elastic perfectly brittle or elastic perfectly plastic trusses. Brick and reinforcement elements are discretized using 4-noded elastic elements. The primary objective is to simulate the potential SRG debonding and the non-linear response of joints under both mode 1 (bending) and mode 2 (shear). Three distinct nonlinear models are employed to explain the behavior at the support-SRG interface: one with a single elastic perfectly brittle truss placed between substrate and strengthening system, the other with two in parallel elastic perfectly brittle trusses, and finally the last one with three parallel trusses, with two being elastic perfectly fragile and one elastic perfectly plastic. These trusses are positioned at the interface between masonry and SRG. For mortar joints, the ultimate tangential strength is determined, accounting for elastic perfectly brittle behavior in tension and infinitely elastic behavior in compression. A Mohr-Coulomb failure criterion is adopted, with a consistent friction angle assumed to remain constant throughout deformation. The computational methodology is validated using a masonry arch reinforced with SRG, comparing against both in-situ experimental data and existing numerical models from literature. Through comprehensive analysis of global force-displacement curves and a thorough examination of model nonlinearities, the method's simplicity and reliability are assessed.