SCEC Award Number 16139 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title Characterization of Basin Effects and Validation of CyberShake and High-F Ground Motions for the Performance-assessment of Tall Buildings
Investigator(s)
Name Organization
Gregory Deierlein Stanford University Ting Lin Marquette University
Other Participants Nenad Bijelic
SCEC Priorities 6e SCEC Groups EEII, GMSV
Report Due Date 03/15/2017 Date Report Submitted 07/30/2017
Project Abstract
 This project focuses on validation and utilization of simulated ground motions in performance-based engineering of tall buildings. The goals are to develop confidence in the use of earthquake simulations in engineering practice and to demonstrate where simulated ground motions provide more reliable hazard estimates compared to conventional hazard analysis using recorded motions. For example, direct assessment using Cybershake simulated motions allows disaggregation of building collapse risk to contributing earthquake ruptures, which is not possible with conventional methods. Earthquake basin effects are identified another prominent ground motion feature that can be more reliably estimated by 3D earthquake simulations as compared to more empirical hazard assessment methods. By examining the unique features of simulated ground motions associated with geologic basins, the analyses help demonstrate how 3D simulations can improve the characterization of basin effects. Key results to date include: (1) for ground motions that are not strongly influenced by basin effects, comparative analyses of recorded and simulated ground motions, which are selected and scaled to the same target spectral intensities and durations, indicate negligible differences in computed building response, (2) differences in collapse risks obtained using conventional methods versus direct assessment with simulated Cybershake motions can generally be attributed to differences in the seismic hazard parameters, as opposed to differences in the ground motion seismographs, (3) differences in building response calculated using conventional versus simulated ground motions in basin locations can arise due to unique characteristics in the response spectra shape and long-period cyclic features of the seismographs.
Intellectual Merit This project contributes to the validation and utilization of earthquake simulations for earthquake engineering applications to the design of buildings and other structures. Comparative analyses of simulated versus recorded ground motions have identified parameters to screen for differences in the ground motions that can have a significant effect on building response, as evaluated using nonlinear response history analyses. The analyses provide feedback to earthquake simulators to (1) identify features in ground motions that are important to building response, and (2) point to significant differences between simulated and recorded earthquakes, where further study is warranted to confirm the reliability of earthquake simulations. To the extent that the differences in simulated and recorded ground motions can be substantiated based on physical reasoning and observations, then the project contributes to identifying where earthquake simulations can have a profound effect on engineering practice.
Broader Impacts This project has contributed to demonstrating the unique value of earthquake simulations to advance engineering practice and thereby enable more realistic and reliable assessment of the safety of buildings and other infrastructure. By engaging with both earth scientists and civil engineers, the project has helped educate and foster communication between the two disciplines that will facilitate technology transfer of earth science into engineering practice. This will serve to improve building codes and inform public policies and initiatives to create more resilient communities.
Exemplary Figure Figure 2. Deaggragation of collapse risk and seismic hazard at the STNI site: (a) mean annual frequency of collapse; (b) Sa(T=3s) hazard; (c) Sa(T=5s) hazard.