The elastic response spectrum method is used in the codes of practice of many countries in which design for earthquakes is of significance in order to facilitate simple design in the form of a linear structural analysis. The procedure involves the computation of a static horizontal substitute loading resulting from the earthquake. The substitute loading is divided by a behavioral factor q in order to take energy dissipation into account, in this work, the q-factors are determined with the aid of dynamic simulation analysis for various steel frame structures subjected to artificially simulated accelerations. The objective of the work is to determine the dependence of the q-factors on the type of structure, the natural periods of oscillation and the duration of the earthquake.