In the past two decades, many investigations have been made on the methods related to the seismic retrofitting of the structures. As the real nonlinear behaviors of the elements are considered in these methods, the values of internal forces determined in the members are equal to the real ones. In the structural seismic linear analysis methods the elements behaviors are still assumed linear. In this regard, the passage of structure through yield point borders and the displacement increasing are correspondent to the forces elevation. In FEMA codes, the factors such as demand modifier (m) or increasing capacity ones are presented applying the effects of elements nonlinear behaviors in linear method analysis. In this research the factors recommended in ASCE 41-06 are studied focusing on several symmetrical and asymmetrical concrete moment resisting frame moldings (5, 7 and 10 stories structures) and linear & non linear time history analysis (7 records). In this regard, the method used for scaling earthquake records is the current method presented in UBC97, “nonlinear dynamic analysis (RHA)”. According to this research there is direct relation between irregularity and increasing the amount of distribution among the results. In this way by increasing the eccentricity, difference between obtained results and recommended values will be more than the case with less irregularity
