Unreinforced masonry arches and vaults are frequent in historic structures worldwide. Many of these structures are subject to deterioration and damage and need strengthening to maintain their stability and preserve the historic value. For design of structural interventions for these structures, analysis is needed to realistically estimate the stresses and deformations after strengthening.The present paper addresses numerical modeling and nonlinear analysis of vaulted masonry vaults structures strengthened by different techniques. The numerical modeling by finite elements and the
nonlinear analysis were carried out using commercial software ANSYS 12.0. The proposed model was applied to study the structural behavior of several brick masonry vaults strengthened by traditional techniques such as steel bars, ferro-cement and polymer mortar layers and also using externally bonded fiber-reinforced polymer (FRP) laminates; the analyzed vaults were previously tested in laboratory till failure. For all the studied vaults, the numerical results obtained using the proposed
model were in good agreement with those obtained experimentally, which demonstrates the capability
of the proposed modeling scheme to simulate efficiently the actual behavior of the strengthened vaults. Comparison of the different strengthening techniques regarding enhancement of the vaults capacity
and stiffness showed that FRP overlays gave higher strengthening level where the failure load was double that of the unstrengthened vaults. The proposed modeling approach is thus considered a valid and practical tool for the design of strengthening interventions for contemporary or historic unreinforced masonry structures.