Earthquake hazards have an effect on significant damage to structures and cause widespread failurernthroughout buildings. Therefore, the assessment of the structural behavior against possiblernearthquakes should be the fundamental point on the design and construction process. rnThe seismic response and/or a performance prediction of buildings assessed based on nonlinearrnstatic analysis as it consumes less time to analysis and provides nearly equally reliable results withrnnonlinear dynamic analysis. rnCurrently, in this research, the methodology is extended to assess the performance of 3D structuralrnsteel frames using a G+10 and G+15 Smart Parking Systems as a case study which are located inrnAddis Ababa city. Imperative issues regarding direction of load application, loading profile,rndiaphragm effects, beam to column joint model and arrangement of incremental static analysisrnresults to generate required data for performance based evaluations have been studied. rnThe result of this research shows that; the curve line for capacity curve (push over curve) of bothrncase study buildings due to applying uniform lateral load distribution is above the capacity curve ofrntriangular lateral load distribution. To this end, Conventional pushover analysis with triangular loadrnpattern distribution gives higher displacement while the uniform lateral load pattern gives higherrnbase shear. The Inter-Storey drift ratio of both the case study buildings is a maximum on the lowerrnstorey of the buildings. Hence, it concluded that failure of buildings due earthquake starts on thernlower storey part of the buildings.