1. Research Scholar, Dept. of Civil and Structural Engineering, Univ. Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
2. Professor, Dept. of Civil and Structural Engineering, Univ. Kebangsaan Malaysia, Bangi, Selangor, Malaysia (corresponding author).,
3. Senior Lecturer, Dept. of Civil and Structural Engineering, Univ. Kebangsaan Malaysia, Bangi, Selangor, Malaysia.