The current paper discusses the contents of the work completed for the project “SERA AIMS – BLIND PREDICTION COMPETITION”. The competition was focused on the prediction of the response of a masonry building composed of two adjacent interacting structural units under earthquake excitation. This research investigates the response of the experimental mock-up by using a numerical model based on the rigid block limit analysis and mathematical programming. The results of the analysis, namely, the failure modes and the corresponding collapse load multipliers, are related to base shear and peak ground accelerations observed for the damage and ultimate limit states using code provisions for the assessment of failure mechanisms in existing masonry structures. Finally, a preliminary comparison of numerical and experiemental results is presented.