Engineering validation of hybrid broadband ground motion simulation using historical events

This paper summarizes the author's efforts in engineering validation of ground motion simulations over the past few years. The Southern California Earthquake Center (SCEC) has established a Technical Activity Group (TAG) focused on Ground Motion Simulation Validation (GMSV) in order to develop and implement testing/rating methodologies via collaboration between ground motion modelers and engineering users. Within the GSMV TAG, a significant bulk of research has been produced in the Performance-Based Earthquake Engineering Laboratory (PBEE-Lab) at the University of California, Irvine (UCI) to validate simulated ground motions for past earthquakes using intensity measures and several engineering demand metrics, i.e., elastic and inelastic response spectra, generalized interstory drift and floor accelerations spectra, buildings and bridge peak responses. In the present paper, we summarize the main results and findings of this ongoing study. In particular, the aim here is to address, on a statistical basis, whether simulated GMs for four historical earthquakes (i.e., Imperial Valley, Landers, Loma Prieta, and Northridge) are systematically biased in terms of median Engineering Demand Parameters (EDPs) of various structural systems (SDoF and MDoF) in comparison with real records. We also investigate the dispersion (i.e., intra-event variability) and the sources of possible differences in the seismic response to recorded and simulated GMs. The results from this study highlight the similarities and differences between synthetic and real records. These similarities should provide confidence in using the simulation methodology for engineering application, while the discrepancies, if statistically significant, should help in improving the generation of synthetic records.