1. University Fellow, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin-Platteville, 1 University Plaza, Platteville, WI 53818-3099; formerly, Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Colorado State Univ., Fort Collins, CO 80523-1372.
2. Professor, Dept. of Civil and Environmental Engineering, Colorado State Univ., 1372 Campus Delivery, Fort Collins, CO 80523-1372 (corresponding author).