This paper presents research concerning the numerical simulation of existing masonry buildings when subjected to pushover analysis. A nonlinear static analysis is undertaken using the commercial software ABAQUS standard, in which masonry structures are modelled using damage mechanics. To validate the chosen input parameters, this study compares two different approaches for static nonlinear modelling, the Finite Element Method (FEM) and the Equivalent Frame Method (EFM), for a simple masonry building. The two methods are compared using the guidelines from Part 3 of Eurocode 8. This study identifies the advantages and disadvantages of various modelling approaches based on the results obtained. The results are also compared in terms of capacity curves and damage distributions for the simple case study of a masonry building created to compare numerical methods. Subsequently, nonlinear pushover analyses with ABAQUS (FEM) were performed on the North Tower of Monserrate Palace, Portugal, in which the material parameters were calibrated by considering the results of dynamic characterisation tests conducted in-situ. Regarding the circular body of Monserrate Palace, the damage distribution of the structure is analysed in detail, aiming to contribute to the modelling of such structural configurations through the Equivalent Frame Method.