1. Graduate Student, Glenn Dept. of Civil Engineering, Clemson Univ., Clemson, SC 29634-0911.
2. Professor, Glenn Dept. of Civil Engineering, Clemson Univ., Clemson, SC 29634-0911 (corresponding author).
3. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of Texas of San Antonio, San Antonio, TX 78249.