1. Professor, Dept. of Civil and Environmental Engineering, Northwestern Univ., Evanston, IL 60208.
2. Assistant Professor, Dept. of Civil Engineering and Construction Engineering Management, California State Univ., Long Beach, CA 90840 (corresponding author).
3. Senior Geotechnical Engineer, GEI Consultants, 2141 Palomar Airport Rd., Carlsbad, CA 92011.