Calculations of earthquake effects can be handled in different ways in current national or international regulations. It is of great importance to consider the second-order effects of properties. After the structural modeling, the designs are completed by using the forces obtained in the section calculations made by considering the earthquake effects. Deformations due to second-order effects can cause greater damage in sections. Within the scope of this study, steel-concrete composite systems, which are produced in Eurocode norms and have remarkable features among structural systems, have been examined. The effects of considering the sensitivity coefficient in the Eurocode in the examinations on the system were evaluated separately in internal and external frames. Especially in elastic design and force-based designs, the effect of this coefficient has been evaluated in buildings with different coefficients in this study. As an example, the number of floors of the studied buildings were modeled as 8, 10, 13 and 15-storey composite moment-resisting frames. During the modeling, the sensitivity coefficient was evaluated to be 0<θ≤0.1 and 0.1<θ≤0.2 in two different intervals. In the evaluations, Nonlinear Time History analyzes, and nonlinear element and material models were used to evaluate the nonlinear behavior. To evaluate the behavior of the systems, the average and maximum values of the interstory drift ratios were carried out. In systems consisting of exemplary composite moment-resisting frames, it has been theoretically evaluated that there were important effects of the use of this coefficient, especially in outer frames.