Structural systems consisting of steel beams and reinforced concrete columns provide an optimal combination of materials in building design. In order to expand the use of such systems, it is very important to address the beam-to-column connection area, discuss the force transfer mechanism, and determine the contribution of load transfer mechanisms. In this study, numerical modeling of the steel beam to a reinforced concrete column connection with a through plate was performed using Abaqus software. Then, the results of the analysis were accurately validated based on the results of experimental tests. In order to evaluate the contribution of the connection components from the connection shear demand, the validated models were expanded to several models with larger dimensions of beam to square and circular column connection. Some models were also analyzed and evaluated to study the effect of shear connectors located on different surfaces of the connection area on load transfer. The results showed that at least 50% and 35% of the connection demands are transferred to the column concrete through the trough plate in the specimens with square and circular columns, respectively. This difference indicates better confinement provided by the circular cover plates. In the specimen without shear connectors, the cover plates were not mobilized in load transfer, which led to increased demand on the through plate, increased stress and strain at the point where the through plate rests on the concrete, and a decrease in the stiffness of the connection.