APPLICATION OF EXTENDED N2 METHOD TO REINFORCED CONCRETE FRAMES WITH ASYMMETRIC SETBACKS

N2 method is a simplified nonlinear static analysis procedure used for the seismic evaluation and design of structures. Recent improvements of this procedure, like the extended N2 method, made the application o f it to irregular structures possible. Asymmetric setback is a common form of vertical irregularity found in multi-storied building frames. The Extended N2 method proposed by Prof. Peter Fajfar is based on the assumption that the structure re mains in the elastic range when vibrating in higher modes. The seismic demand in terms of displacements and storey drifts can be obtained by enveloping the results of basic pushover analysis and the results of standard elastic modal analysis.