1. Professor, Glenn Dept. of Civil Engineering, Clemson Univ., Clemson, SC 29634; and Professor, Dept. of Civil Engineering, National Central Univ., Jungli, Taoyuan 32001, Taiwan (corresponding author).
2. Visiting Assistant Professor, Glenn Dept. of Civil Engineering, Clemson Univ., Clemson, SC 29634; formerly, Research Assistant, Glenn Dept. of Civil Engineering, Clemson Univ., Clemson, SC 29634.
3. Assistant Professor, Glenn Dept. of Civil Engineering, Clemson Univ., Clemson, SC 29634.
4. Professor, Dept. of Geotechnical Engineering, Tongji Univ., Shanghai 200092, China.