Ground-motion model for the standardized version of cumulative absolute velocity

Abstract

After publishing its original definition of cumulative absolute velocity ( CAV), the Electric Power Research Institute (EPRI) proposed a standardized version of CAV that it recommended is a better indicator of damage to structures of good design and construction than CAV. We refer to this intensity measure (IM) as CAVSTD. EPRI proposed 0.16 g-s (1.57 m/s) as the threshold value of CAVSTD that corresponds to the onset of damage to structures of good design and construction. Although this damage threshold was conservatively applied to nuclear power plants, its development using recordings from sites subjected to MMI VII shaking suggests that it is appropriate for civil structures. In 2011, we developed a ground-motion model (GMM) for the version of CAVSTD that was adopted by the US Nuclear Regulatory Commission for determining when a nuclear power plant must be shut down for inspection after an earthquake, which we called CAVDP. In this study, we develop a GMM for CAVSTD conditioned on values of CAV and peak ground acceleration ( PGA) using an extensive database of recordings compiled for the NGA-West2 project. We demonstrate how the conditional GMM developed in this study can be used together with predicted values of CAV and PGA to provide unconditional estimates of CAVSTD and its standard deviations when values of these IMs are unknown.

Ground-motion model for Housner’s spectrum intensity based on a novel hybrid-scenario approach

“… CA V STD is negatively correlated with PSA at short periods and becomes virtually uncorrelated with PSA at moderate-to-long periods. This latter behavior is discussed in Campbell and Bozorgnia (2023). Similar correlations are found for the within-event residuals because of their significant contribution to the total residuals.…”

“…Figure 7 plots the median correlation coefficients and their two standard-error bounds of CAV , AI , SI , and CA V STD versus PSA ( T = 0 . 01 − 10 s ) using the values listed in Supplemental Table S2. This figure updates a similar figure in Campbell and Bozorgnia (2023). It excludes plots of correlation coefficients of PGA and PGV to focus on those cumulative IMs considered to be more closely related to damage.…”

“…Bradley, 2012). Table S2 in the Supplemental Material lists the mean Pearson correlation coefficients and their two standard-error bounds (a confidence interval of ~98%) for the M ≤ 4 . 5 and M ≥ 5 . 5 magnitude ranges among the residuals of SI from the hybrid-scenario model of this study, AI (Arias intensity) and CAV from Campbell and Bozorgnia (2019), CA V STD (standardized version of CAV ) from Campbell and Bozorgnia (2023), and PGA , PGV , and PSA from CB14. AI , CAV , and CA V STD are defined in terms of the as-recorded geometric-mean horizontal component of ground motion.…”