SCEC Award Number 17056 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Selection of CyberShake Time Series for Engineering Building Code Analyses
Name Organization
Jack Baker Stanford University
Other Participants 1 PhD student (tentatively, Ganyu Teng)
SCEC Priorities 4d, 4c, 4b SCEC Groups CS, GM, EEII
Report Due Date 06/15/2018 Date Report Submitted 07/19/2018
Project Abstract
This report evaluates the application of CyberShake ground motions to high-rise building design in the Los Angeles region. We compare simulated ground motions against past earthquake records and empirical models. First, we considered two selected sites in the Los Angeles region with different underlying soil conditions and selected comparable suites of ground motion records from CyberShake and the NGA-West2 database according to the ASCE 7-16 requirements. We evaluated their corresponding ground motion characteristics including intensity measures, deaggregation, polarization and durations. Major observations include 1) Selected ground motions from CyberShake and NGA-West2 share similar features, in terms of intensity measures and polarization; 2) When selecting records from CyberShake, it is easy to specify magnitudes, distances and faults to match the hazard deaggregation; 3) CyberShake durations on soil are consistent with empirical models, whereas durations on rock are shorter. This inconsistency may be due to limited recorded earthquakes. 4) Occasional excessive polarization in ground motion is produced by the San Andreas fault. Those records are usually excluded after the ground motion selection.

Selected results are presented below. The results provide further insights regarding the value of physics-based ground motion simulations for engineering use.
Intellectual Merit The search and selection of ground motions provides an understanding of the suitability of CyberShake ground motions for practical engineering analysis.
Further, the selected motions have been shown to practicing engineering consultants working on tall buildings projects, in order to understand their interest in the insights provided by these motions, and to understand the documentation that they would desire before adopting such ground motions on real-world projects.
Availability of this easy-to-access set of suitable ground motions will also encourage engineers to utilize simulations in real-world projects.
Broader Impacts The selected data has been packaged as an easy-to-digest subset, rather than a comprehensive set of data, in order to facilitate interaction with a group of users that would never utilize traditional SCEC data resources.
The transfer and evaluation of these data by users will provide helpful feedback to SCEC about the suitability of these data, and about desired documentation of the data.
This feedback will allow for more effective development of future databases of ground motions, by addressing identified user needs.
Exemplary Figure Figure 2. Comparison of target spectrum and selected response spectra from (a) CyberShake for LADT, (b) NGA-West2 for LADT, (c) CyberShake for PAS, (d) NGA-West2 for PAS.