Unscaled Real Record Sets Compliant With Eurocode 8

Among all possible options, natural recordings are emerging as the more attractive input for non-linear dynamic analysis since accessible waveform databases are available and some evidences show that only a limited number of criteria have to be considered in selection to get unbiased estimation of seismic demand. The Eurocode 8 allows the use of real ground motions for the nonlinear seismic analysis of structures. The main constraint to be satisfied by the chosen record set is the matching, of the average spectral ordinates, with the elastic code spectra. In fact, the latter may not be underestimated more than by 10% in a broad range of periods. Code’s spectral shape depends on the seismicity of the site, which may be obtained by national seismic surveys (Italian herein), and on the soil conditions. The study presented in the paper investigated the European Strong Motion Database to establish whether combinations of unscaled records complying with the Eurocode 8 prescriptions, and also accounting for additive constraints believed to matter in the non-linear assessment of buildings, may be found. Results refer to soft soils, stiff soils and rock. The accelerogram sets obtained tend to overestimate as minimally as possible the code’s spectrum for economical reasons; to have the minimum record-to-record variability; and are not manipulated (i.e. not scaled), to avoid “epsilon” related issues.