Robust Earthquake Site Classification Assessment at Ontario Bridge Sites.

Author

Alex Bilson Darko, The University of Western OntarioFollow

Degree

Master of Science

Program

Geophysics

Supervisor

Molnar, Sheri

2nd Supervisor

Sadrekarimi, Abouzar

Abstract

Canadian seismic design guidelines classify subsurface ground conditions based on the average shear-wave velocity (V_S) of the upper 30 meters (V_S30). We seek to optimize a robust earthquake site classification procedure for Ontario bridge sites, assessed primarily from blind comparison of non-invasive V_S depth profiling techniques. Non-invasive seismic testing is performed at 10 bridge sites in southern Ontario co-located with invasive penetration and/or borehole V_S measurements. Non-invasive surface wave dispersion and site amplification functions are jointly inverted to retrieve V_S profiles at each site. A general correlation between corrected V_S and cone tip resistance (q_c1) is developed for all soils encountered in Windsor, Ontario. We determine an overall average relative difference in V_S between methodologies of 17% for soil layers at all bridge sites. Earthquake site classification based on V_S is consistent at all sites regardless of methodology. Non-invasive techniques offer an efficient but lower-resolution V_S profiling alternative to invasive earthquake site classification techniques with the advantages of measuring site period and V_S of the impenetrable substratum.

Recommended Citation

Bilson Darko, Alex, "Robust Earthquake Site Classification Assessment at Ontario Bridge Sites." (2018). Electronic Thesis and Dissertation Repository. 5903.
https://ir.lib.uwo.ca/etd/5903