P. Fajfar - University of Ljubljana, Faculty of Civil
M. Dolšek - Geodetic Engineering Ljubljana, Slovenia

Simplified non-linear procedures, which combine the non-linear static (pushover) analysis of a relatively simple mathematical model and the response spectrum approach, represent a shortterm trend in seismic design. In recent years, a breakthrough of these procedures has been observed. They have been implemented into the modern guidelines and codes. In the paper the similarities and differences between different procedures, the approximations and limitations of the simplified inelastic methods, and the direct displacement-based design are discussed. Although different methods may yield in many cases similar results, they differ in respect to simplicity, transparency and clarity of theoretical background. The most important difference is related to the determination of displacement demand. The major attention is focused on the N2 method, which has been implemented into the recent draft of the Eurocode 8 standard. The extension of the method, which allows the application of the method to infilled frames, is presented and applied to a test example.