1. Graduate Student, Dept. of Civil and Environmental Engineering, Univ. of Maryland, College Park, MD 20742; formerly, Graduate Student, Dept. of Civil Engineering, Univ. of Nebraska-Lincoln, Omaha, NE 68182 (corresponding author).
2. Professor, Dept. of Civil Engineering, Univ. of Nebraska-Lincoln, Omaha, NE 68182.
3. Associate Professor, Dept. of Civil Engineering, Univ. of Nebraska-Lincoln, Omaha, NE 68182.
4. Engineer, Water Supply and Water Resources Division, U.S. Environmental Protection Agency, Cincinnati, OH 45268.
5. NIST Fellow, Materials and Structural Systems Division, National Institute of Standards and Technology, Gaithersburg, MD 20899.