Proposal of a Selection Criterium of Natural Accelerograms for NLRHA

Abstract

A selection criterion to obtain different sets of accelerograms, all of them satisfying the spectrum compatibility criteria imposed by the codes, that enable a reliable assessment of the seismic demand for a given structure is proposed. The formulation is based on a preliminary evaluation of correlations among Intensity Measure parameters for ground motion and cinematic, energetic and damage parameters describing structure non linear responses. To this aim, a modified expression of the Effective Peak Acceleration EPA* is proposed, defined over the range of structure fundamental period referring to undamaged and damaged model. The analyses are carried out analyzing the response of a three plane multi-storey Reinforced Concrete Moment Resisting Frames (RCMRFs) to a set of 60 different accelerograms, and analyzing the value of the correlation coefficients between input Intensity Measure and structure response parameters. Then, a new selection criterion for accelerogram sets based on the minimum value of the Coefficient of Variation (CoV) of the EPA* is proposed. Effectiveness is proved by evaluation of average values and COV of NLRHA response parameters for the RCMRFs.