1. Graduate Student, Univ. of Waterloo, Dept. of Civil and Environmental Engineering, 200 University Ave. W., Waterloo, ON N2L 3G1, Canada (corresponding author).
2. Professor, Univ. of Waterloo, Dept. of Civil and Environmental Engineering, 200 University Ave. W., Waterloo, ON N2L 3G1, Canada.
3. Associate Professor, Univ. of Kentucky, College of Engineering, Dept. of Civil Engineering, Lexington, KY 40506-5416.
4. Assistant Professor, Univ. of Texas at Austin, Dept. of Civil, Architectural, and Environmental Engineering, 1 University Station C1752, Austin, TX 78712-0273.