1. Project Geotechnical Engineer, Terracon, 13050 Eastgate Park Way, Suite 101, Louisville, KY 40223; formerly, Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Michigan, Ann Arbor, MI 48109.
2. Professor, Dept. of Civil and Environmental Engineering, Univ. of Michigan, Ann Arbor, MI 48109 (corresponding author).