1. Assistant Professor, School of Civil Engineering, Purdue Univ., 550 Stadium Mall, West Lafayette, IN 47907-2051 (corresponding author).
2. Assistant Professor, School of Civil Engineering, Purdue Univ., 550 Stadium Mall, West Lafayette, IN 47907-2051.
3. Principal Research Associate, Dept. of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139.