1. Ph.D. Student, Dept. of Civil and Environmental Engineering, Stanford Univ., Stanford, CA 94305 (corresponding author).
2. Assistant Professor, Dept. of Civil Engineering, Lakehead Univ., Thunder Bay, ON, Canada P7B 5E1.
3. Professor, Dept. of Civil Engineering, Univ. of Toronto, Toronto, ON, Canada M4S 1A4.