Modelling issues and pushover response of singlestory older steel buildings

The paper describes a study concerning the seismic response of some typical non-residential single-story older steel buildings. To this end, the design of two archetype buildings was simulated according to structural codes and standards of practice used in Italy in the 1980s-1990s. The basic structural layout was assumed to be made of trussed portals in the transverse direction and con centric braces in the longitudinal direction. In the direction of the trussed portals, two alternative structural options were considered: (a) a pinned column base with moment action provided by the truss, and (b) a semi-continuous column base with a pinned connection between the truss and the column top cross section. 3D finite element non-linear models of the two case study structures were built. The model included the main frame members, some critical connections and explicit representation of fracture propagation for braces. Results from non-linear static analysis are then presented and discussed. The paper highlights differences in the structural response due to differ ences in the selected design options, comparing both global and local response results.