1. Member, ASCE
2. Prof., Dept. of Civ. Engrg., Nat. Univ. of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (corresponding author). E-mail: cvefwatf@ nus.edu.sg
3. Assoc. Prof., Dept. of Civ. Engrg., Nat. Univ. of Singapore, 10 Kent Ridge Crescent, Singapore.
4. Res. Scholar, Dept. of Civ. Engrg., Nat. Univ. of Singapore, 10 Kent Ridge Crescent, Singapore.