Implications of next generation attenuation ground motion prediction equations for site coefficients used in earthquake resistant design

Earthquake Engineering and Structural Dynamics
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Abstract

Proposals are developed to update Tables 11.4-1 and 11.4-2 of Minimum Design Loads for Buildings and Other Structures published as American Society of Civil Engineers Structural Engineering Institute standard 7-10 (ASCE/SEI 7–10). The updates are mean next generation attenuation (NGA) site coefficients inferred directly from the four NGA ground motion prediction equations used to derive the maximum considered earthquake response maps adopted in ASCE/SEI 7–10. Proposals include the recommendation to use straight-line interpolation to infer site coefficients at intermediate values of math formula(average shear velocity to 30-m depth). The NGA coefficients are shown to agree well with adopted site coefficients at low levels of input motion (0.1 g) and those observed from the Loma Prieta earthquake. For higher levels of input motion, the majority of the adopted values are within the 95% epistemic-uncertainty limits implied by the NGA estimates with the exceptions being the mid-period site coefficient, Fv, for site class D and the short-period coefficient, Fa, for site class C, both of which are slightly less than the corresponding 95% limit. The NGA data base shows that the median value math formula of 913 m/s for site class B is more typical than 760 m/s as a value to characterize firm to hard rock sites as the uniform ground condition for future maximum considered earthquake response ground motion estimates. Future updates of NGA ground motion prediction equations can be incorporated easily into future adjustments of adopted site coefficients using procedures presented herein. 

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Implications of next generation attenuation ground motion prediction equations for site coefficients used in earthquake resistant design
Series title Earthquake Engineering and Structural Dynamics
DOI 10.1002/eqe.2400
Volume 43
Issue 9
Year Published 2014
Language English
Publisher Wiley
Contributing office(s) Earthquake Science Center
Description 18 p.
First page 1343
Last page 1360