1. Lecturer, Dept. of Civil and Environmental Engineering, Univ. of North Carolina at Charlotte, Charlotte, NC 28223.
2. Professor, Dept. of Civil and Environmental Engineering, Univ. of Utah, 110 Central Campus Dr., Salt Lake City, UT 84112 (corresponding author).
3. Professor Emeritus, Dept. of Civil and Environmental Engineering, Univ. of Utah, 110 Central Campus Dr., Salt Lake City, UT 84112.