1. SDR Engineering, 3370 Capital Circle NE, Ste. G, Tallahassee, FL 32308. E-mail: hliu@sdrengineering.com
2. Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Massachusetts, 223 Marston Hall, 130 Natural Resources Rd., Amherst, MA 01003 (corresponding author). E-mail: arwade@ecs.umass.edu
3. Professor, Dept. of Civil Engineering, Johns Hopkins Univ., 3400 N. Charles St., Baltimore, MD 21218. E-mail: tigusa@jhu.edu