1. Civil Engineering Department, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM-Serdang, Malaysia; Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM-Serdang, Malaysia
2. College of Engineering, Geotechnical Engineering Faculty, King Saud University, Riyadh, Saudi Arabia
3. Civil Engineering Department, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM-Serdang, Malaysia