1. Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Maryland, College Park, MD 20742.
2. Professor, Dept. of Civil and Environmental Engineering, Univ. of Maryland, College Park, MD 20742. E-mail: rhmccuen@eng.umd.edu
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of Maryland, College Park, MD 20742.