1. Associate Professor, Dept. of Civil and Environmental Engineering, Texas Tech Univ., Lubbock, TX 79409 (corresponding author).
2. Associate Professor, Dept. of Civil and Environmental Engineering, Texas Tech Univ., Lubbock, TX 79409.
3. Research Associate, Dept. of Civil and Environmental Engineering, Texas Tech Univ., Lubbock, TX 79409.
4. Professor, Dept. of Mathematics and Statistics, Texas Tech Univ., Lubbock, TX 79409.