1. Staff Engineer, Earth Mechanics, Inc., 3541 Investment Blvd. #4, Hayward, CA 94545, USA,
2. Senior Staff Engineer and Laboratory Research Scientist, Hushmand Associates, Inc., 250 Goddard, Irvine, CA, USA,
3. Professor and Department Chair, Department of Structural Engineering, University of California, San Diego, La Jolla, CA, 92093-0085, USA,(corresponding author)