Simplified Performance Based Nonlinear Static Evaluation of Existing Building—N2 Method

The nonlinear static (pushover) procedure for estimating target displacement is incorporated in Annex B of Eurocode 8 and is commonly implemented through the N2 method, originally developed at the University of Ljubljana. While advanced nonlinear dynamic analyses can provide detailed insight into seismic structural behavior, they require sophisticated modeling and significant computational effort. In contrast, simplified procedures are often preferred in engineering practice for preliminary assessment and design verification. This study evaluates the applicability of the N2 method by comparing analytically obtained target displacements with experimentally measured responses of a three-story model building subjected to seismic excitation. The nonlinear capacity curve derived from pushover analysis is transformed into the acceleration–displacement response spectrum (ADRS) domain and evaluated against the demand spectrum to determine the performance point. The experimentally obtained value, reported in a reference study, is used as a benchmark for assessment. The results indicate that the N2 method provides an approximate but rapid estimation of target displacement. The findings highlight both the practical usefulness and the inherent limitations of the N2 approach when applied to structures.