1. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Nevada, Reno, NV 89557-0258 (corresponding author).
2. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Washington, Seattle, WA 98195-5502.
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of Nevada, Reno, NV 89557-0258.
4. Professor, Dept. of Civil and Environmental Engineering, Univ. of Washington, Seattle, WA 98195-5502.