1. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Mathews Ave., MC-250, Urbana, IL 61801 (corresponding author).
2. Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Mathews Ave., MC-250, Urbana, IL 61801.
3. Associate Professor, Dept. of Civil, Construction, and Environmental Engineering, NC State Univ., CB 7908, Raleigh, NC 27695.