1. Dept. of Civil Engineering and Engineering Mechanics, Columbia Univ., 610 Sleeley W. Mudd 500 West 120th St., New York, NY 10027.
2. College of Science and Technology, North Carolina A&T State Univ., 1601E. Market St., Greensboro, NC 27405.
3. Dept. of Civil and Environmental Engineering, Manhattan College, 4513 Manhattan College Parkway, Riverdale, NY 10471.
4. Arizona State Univ., 660 S. College Ave., Tempe, AZ 85287-3005 (corresponding author).