1. Graduate Student Researcher, Dept. of Civil and Environmental Engineering, Univ. of California, 116 McLaughlin Hall, Berkeley, CA 94720-1720 (corresponding author).
2. Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Massachusetts, 216 Marston Hall, 130 Natural Resources Rd., Amherst, MA 01003-0724.
3. Postdoctoral Researcher, Dept. of Civil and Environmental Engineering, Univ. of California, 416 McLaughlin Hall, Berkeley, CA 94720-1720.
4. Xenel Professor of Engineering, Dept. of Civil and Environmental Engineering, Univ. of California, 109 McLaughlin Hall, Berkeley, CA 94720-1720.