Quantification of Ground Motion Uncertainties Based on Fuzzy Set Mathematics
 

Sara Wadia-Fascetti
    Assistant Professor, Northeastern University

H. Allison Smith
    Assistant Professor, Stanford University

Anne S. Kiremidjian
    Professor, Stanford University

 

ABSTRACT

In order to mitigate damage due to earthquakes, engineers use design response spectra to predict the potential maximum response that the structure may experience.  However, uncertainties due to local site conditions, distance from the site to the earthquake, structural damping, earthquake magnitude, and soil-structure-interaction typically are not considered in development of design response spectra.  This study formulates earthquake response spectra based on use of fuzzy mathematics to represent and quantify uncertainties associated with site conditions and the earthquake parameters.

Fuzzy velocity response spectra based on a 5% structural damping coefficient are developed from Loma Prieta earthquake time histories such that membership functions quantify the error in the response spectra.  In the development of the spectra, its assumed that a general soil type is known for the site; thus, rock and alluvium conditions are considered separately.  Additionally, the spectra are divided into three additional categories representing sites at distances less than 30 km, between 30 and 60 km, and larger than 60 km form the fault rupture.
 

Contact Information:

Prof. S. Wadia-Fascetti (swf@neu.edu)
Dept. of Civil & Env. Engineering
Northeastern University
Boston, MA  02115

Reference:

Wadia-Fascetti, S., Smith, H. A., and Kiremidjian, A. S., (1994) “Quantification of Ground Motion Uncertainties Based on Fuzzy Set Mathematics.” Proceedings of the 5th National Conference on Earthquake Engineering.  Chicago, IL, July 10 - 14, 1994.

Back to: publications page
Back to: group home page