A simplified approach for the estimation of seismic vulnerability of steel moment resisting frames

In recent years, the numerous seismic events occurred have pointed out the need for a prompt classification of the built heritage in terms of seismic vulnerability. the concept of vulnerability is closely linked to the definition of the capacity curve, requiring sophisticated numerical procedures to be perferomed, such as the inelastic incremental analysis. Therefore, the simplified method herein proposed requires use of only analytically simple analyses such as the elastic analysis and the rigid-plastic analysis. For this reason, this method can be used in the immediate aftermath of an earthquake and also for a large-scale classification of the buildings. The proposed methodology has been set up by a wide parametric analysis, carried out on 420 frames designed according to 3 different approaches: the first one is linked to the Theory of Plastic Mechanism Control (TPMC), assuring the design of structures showing global collapse mechanism (GMRFs), the second is based on the Eurocode 8 requirements (SMRFs) while the third is a non-seismic design, based on vertical loads (OMRFs).