1. PhD Candidate, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, B233 Newmark Civil Engineering Laboratory, MC-250, 205 North Mathews Ave., Urbana, IL 61801.
2. Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 1211 Newmark Civil Engineering Laboratory, MC-250, 205 North Mathews Ave., Urbana, IL 61801 (corresponding authors).