1. Professor, Dept. of Civil Engineering, The Catholic Univ. of America, Washington, D.C. 20064 (corresponding author).
2. Director, US Power Generating Company, LLC, 505 Fifth Ave., 21st floor, New York, NY 10017.
3. Professor, Dept. of Civil & Environmental Engineering, Cheju National Univ., 66 Jejudaehakno, Jeju-Do 690-756, Korea.