1. Dept. of Civil and Environmental Engineering, Michigan Technological Univ., 1400 Townsend Dr., Houghton, MI 49931-1295 (corresponding author).
2. Dept. of Civil and Environmental Engineering, Michigan Technological Univ., 1400 Townsend Dr., Houghton, MI 49931-1295.
3. Civil and Environmental Engineering, North Carolina A&T State Univ., 434 McNair Hall, 1601 E. Market St., Greensboro, NC 27411.