1. Ph.D. Student, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin, 2256 Engineering Hall, 1415 Engineering Dr., Madison, WI 53706.
2. Assistant Professor and John L. Tishman Faculty Scholar, Dept. of Civil and Environmental Engineering, Univ. of Michigan, 2322 G.G. Brown, 2315 Hayward St., Ann Arbor, MI 48109 (corresponding author).