A reinforced concrete frame filled with masonry is a common structural system for low and medium high buildings in Europe's seismically active areas. In accordance with current knowledge about earthquake effects, the structural system consists of seismic resistance elements, frames made of reinforced concrete or steel and infill wall, in Croatia usually made of brick blocks or concrete. In masonry infill wall are mostly found the apertures of different sizes, forms and location, which can be stiffened with r.c.confining element that contribute to the system’s additional stability and rigidity. The infill wall significantly influences the response of the structure to the earthquake action and this influence must be appropriately taken into account when calculating. Numerical procedures for determining earthquake resistance must be used very carefully in accordance with earthquake engineering regulations. Mostly, the reason for this is insufficient understanding of this impact. The infill wall is usually modeled with a diagonal pressure rod. When calculating, the thickness of the rod is equal to the thickness of the wall, and the width of the rod is determined. The width of the rod is not easy to determine - there are multiple approaches from which we determine the most appropriate. The numerical model was created in the Athens 2D Engineering computer program using finite element method (FEM). It has been created s nonlinear numerical micro model in which the nonlinear behavior of reinforcement, concrete, filler elements, blocks and mortar was modeled. Numerical models are quite sensitive to input data, so data should be entered carefully. The numerical models are very good substitution for the actual experimental models because they give high-quality results. This paper investigates the behavior and shear resistance of a frame-wall structural system in the case of a non-displaced door opening with r.c.confining element when simulating an earthquake in its own plane. For this purpose, it is necessary to develop a spatial model using finite element methods (FEM) in the ATHENS 2D computer program to determine the positive resistance of the system in its own plane. The results of the experimental tests will be compared with those of the ATHENS 2D numerical procedures.