1. Associate Professor, Dept. of Civil, Environmental, and Architectural Engineering, Univ. of Colorado, 428 UCB, Boulder, CO 80309.
2. Postdoctoral Researcher, Dept. of Civil, Environmental, and Architectural Engineering, Univ. of Colorado, 428 UCB, Boulder, CO 80309 (corresponding author).
3. Research Scientist II, SAIC, Billerica, MA 01821.
4. Professor, Dept. of Civil, Environmental, and Architectural Engineering, Univ. of Colorado, 428 UCB, Boulder, CO 80309.