Southern California Earthquake Center (SCEC) CyberShake Research Project - Use in Building Design/Analysis

摘要

CyberShake is a research project in Southern California Earthquake Center (SCEC). This project aims at the development of a physics-based computational approach for probabilistic seismic hazard analysis (PSHA). The purpose of the project is to generate ground motions for southern California in a manner that computationally accounts for effects such as basin effects and focusing of waves due to varying stratigraphy. The completed project incorporates these probabilistic ground motions along with deterministic ground motion caps such that the site-specific requirements of ASCE 7-16 are met in development of site-specific response spectra. The impetus of this project is the well-known basin effects of the Los Angeles Basin and surrounding valleys such as the San Fernando Valley and San Gabriel Valley. These computations were performed for spectral periods of 2 seconds and greater and therefore Cybershake-generated ground motions would impact the design of taller buildings and other long-period structures. A user-friendly web-based tool has been developed to provide these ground motions to users. Jurisdictions including the City of Los Angeles are considering requiring the use of Cybershake response spectra where they produce greater motions than current code spectra. This paper provides a comparison of spectra based on ASCE 7-16 and generated by CyberShake, and commentary on the results of application of the Cybershake model on the design of expected building types in selected locations of southern California.