1. Research Scientist, Dept. of Civil and Environmental Engineering, Univ. of Virginia, 351 McCormick Rd., Charlottesville, VA 22904 (corresponding author).
2. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of Virginia. Charlottesville, VA 22904.
3. Assistant Professor, Division of Environmental, Civil and Transportation Engineering, Ajou Univ., San 5, Wonchon-Dong, Yeongtong-Gu, Suwon, Kyunggi-Do 443-749, Korea.