Assessing three real RC buildings using different accelerogram selection approaches

Within the realms of seismic vulnerability assessment of existing structures, current seismic codes, such as EC8 and the Italian code (NTC), allow the use of nonlinear dynamic analysis. The application of this analysis method requires the seismic action to be represented by a suite of ground motion records, whose selection should be compatible with a reference spectrum. Since the selection and scaling of accelerograms is still an “evolving” topic both for researchers and practitioners, the main goal of this work is to investigate the impact that different selection strategies may or may not have in the seismic assessment of existing structures. For this purpose, three real RC buildings were considered, and nonlinear dynamic analyses were performed in order to evaluate the structural performance at the element level (by carrying out the capacity checks in terms of element chord rotation, as well as shear resistance). Furthermore, a “seismic risk index”, defined as the ratio (in terms of PGA) between the capacity and the demand at the ultimate limit state (i.e. SLV referring to the Italian code), was computed for each performed analysis. A comparison was made of the results obtained with the different accelerogram selection approaches and between each case-study.