The seismic assessment of R.C. frame buildings using Italian code and Eurocode: some considerations

The seismic assessment of existing structures is a priority in Italy and in other European countries, since the majority of the building heritage was designed according to past codes, either devoid of - or lacking in - seismic provisions. Different procedures may be applied according to the Italian Code and to EuroCode 8, depending on the level of knowledge of the structure. Linear analysis is used when available information is scanty, but selecting a suitable behavior factor is very difficult because of the uncertainties about the nonlinear behavior of the structure. On the other hand, nonlinear analysis requires accurate data about the structure and its materials, to yield reliable results, and the assessment of the structural response requires long and complex calculations. In this work, the assessment of four irregular r.c. existing buildings, all characterized by a frame-type structure with different configurations, is performed with the following objectives: (1) to propose simplified approaches and improvements for the assessment procedure; (2) to compare the results of linear and nonlinear analysis methods.