An Algorithm for Selecting Spatially Correlated Ground Motions at Multiple Sites under Scenario Earthquakes

This paper presents an algorithm to select records from a ground motion database for multiple sites under unconditional or conditional earthquake scenarios. Major steps in the selection algorithm are to construct the target distribution (i.e., mean and covariance matrix) of spectral accelerations (SAs) at multiple sites by incorporating the ground-motion spatial correlation, randomly simulate suites of response spectra given the target, and select a final suite of recorded ground motions with response spectra individually matching the simulated spectra. Ground-motion selection examples are provided to validate the performance of the algorithm developed; it is demonstrated that the selected multiple-site ground motions realistically capture the target distribution (i.e., mean, covariance, and spatial correlation) of response spectra for both unconditional and conditional scenarios. The computational expense of the algorithm is examined to be generally acceptable. The algorithm presented can be used for selecting ground motions, as inputs to conduct dynamic analysis of spatially distributed buildings.

Automated summary

This paper presents an algorithm for selecting ground motions from a database for multiple sites under earthquake scenarios. The algorithm constructs the target distribution of spectral accelerations at multiple sites by considering the spatial correlation of ground motions. It then randomly simulates response spectra and selects recorded ground motions that match the simulated spectra. Validation examples demonstrate that the selected ground motions realistically capture the target distribution of response spectra. The computational expense of the algorithm is found to be generally acceptable. The algorithm can be used for selecting ground motions as inputs for dynamic analysis of spatially distributed buildings.