1. Design Engineer, Degenkolb Engineers, 600 University St., Suite 720, Seattle, WA 98101 (corresponding author).
2. Professor, Oregon State Univ., School of Civil and Construction Engineering, 101 Kearney Hall, Corvallis, OR 97331.
3. Professor, Purdue Univ., Lyles School of Civil Engineering, West Lafayette, IN 47907.