1. Postdoctor Fellow, Dept. of Civil and Environmental Engineering, Colorado State Univ., Fort Collins, CO 80523-1372.
2. Harold H. Short Endowed Chair, Dept. of Civil and Environmental Engineering, Colorado State Univ., Fort Collins, CO 80523-1372 (corresponding author).
3. Professor, School of Civil and Construction and Engineering, Oregon State Univ., Corvallis, OR 97331-2302.