1. Former Research Assistant, Dept. of Civil Engineering, Clemson Univ., Clemson, SC 29634-0911.
2. Research Assistant Professor, Dept. of Civil Engineering, Clemson Univ., Clemson, SC 29634-0911 (corresponding author).
3. Professor, Dept. of Civil Engineering, Clemson Univ., Clemson, SC 29634-0911.