1. Postdoctoral Associate, Civil and Environmental Engineering, Univ. of Maryland, 1173 Glenn L. Martin Hall, 4298 Campus Dr., College Park, MD 20742.
2. Associate Professor, Civil and Environmental Engineering, Univ. of Maryland, 1173 Glenn L. Martin Hall, 4298 Campus Dr., College Park, MD 20742 (corresponding author).
3. Professor, Civil and Environmental Engineering, Univ. of Maryland, 1173 Glenn L. Martin Hall, 4298 Campus Dr., College Park, MD 20742.