1. Dept. of Civil and Environmental Engineering, Univ. of Alberta, Edmonton AB, Canada T6G 2W2. E-mail: canhua@ualberta.net
2. Professor, Dept. of Civil and Environmental Engineering, Univ. of Alberta, Edmonton AB, Canada T6G 2W2 (corresponding author). E-mail: David.Zhu@ ulaberta.ca
3. Emeritus Professor, Dept. of Civil and Environmental Engineering, Univ. of Alberta, Edmonton AB, Canada T6G 2W2. E-mail: nrajaratnam@ualberta.ca