1. Ph.D. Candidate, Dept. of Civil and Environmental Engineering, Univ. of Michigan, 2350 Hayward St., Room 1316 G.G. Brown Bldg, Ann Arbor, MI 48109.
2. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of Michigan, 2350 Hayward St., Room 2340 G.G. Brown Bldg, Ann Arbor, MI 48109 (corresponding author).