1. Assistant Professor, Dept. of Civil and Environmental Engineering, Michigan Technological Univ., 1400 Townsend Dr., 201F Dillman Hall, Houghton, MI 49931 (corresponding author).
2. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 1211 Newmark Civil Engineering Laboratory, 205 N. Mathews Ave, Urbana, IL 61801.