The seismic design of steel moment resisting frames (MRFs) according to EC8 is largely influenced by the lateral stability checks. North American codes (e.g. ASCE7) impose different rules to verify the sensitivity of the structures to P-Delta effects. In this manuscript, both current EC8 and ASCE7 rules are compared against a possible alternative. The relevant implications on the design and performance of frames are also investigated by means of static and dynamic nonlinear analyses. The obtained results show that the rules given by EN1998-1-1 lead to overdesigned MRFs as respect to the structures designed according to ASCE7. The structures designed according to the recent modified version of the EN1998-1-1 gives solutions closer to North American codes
