1. Postdoctoral Research Fellow, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin-Madison, Madison, WI 53706 (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin-Madison, Madison, WI 53706.
3. Wisconsin Distinguished Professor and Chair, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin-Madison, Madison, WI 53706.