1. Ph.D. Student, Dept. of Civil and Environmental Engineering, 1316 G. G. Brown Building, 2350 Hayward St., Univ. of Michigan, Ann Arbor, MI 48109.
2. Assistant Professor, Dept. of Civil and Environmental Engineering, 2340 G. G. Brown Building, 2350 Hayward St., Univ. of Michigan, Ann Arbor, MI 48109 (corresponding author).
3. Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Michigan, 2322 G. G. Brown Building, 2350 Hayward St., Ann Arbor, MI 48109; formerly, M.A. Mortenson Company Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin, 2318 Engineering Hall, 1415 Engineering Dr., Madison, WI.