1. School of Civil and Environmental Engineering, Cornell Univ., 319 Hollister Hall, Ithaca, NY 14853; presently, WSP USA, 444 S Flower St. #800, Los Angeles, CA 90071 (corresponding author).
2. Professor, School of Civil and Environmental Engineering, Cornell Univ., Ithaca, NY 14853.
3. Associate Professor, School of Civil and Environmental Engineering, Cornell Univ., Ithaca, NY 14853.
4. Research Associate, Dept. of Civil, Environmental, and Architectural Engineering, Univ. of Colorado Boulder, Boulder, CO 80309.