1. Graduate Research Assistant, Charles E. Via, Jr. Dept. of Civil and Environmental Engineering, Virginia Polytechnic Institute and State Univ., 200 Patton Hall, Blacksburg, VA 24060 (corresponding author).
2. Assitant Professor, Dept. of Civil and Environmental Engineering, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801.
3. Undergraduate Research Assistant, Dept. of Civil and Environmental Engineering, New Mexico Institute of Mining and Technology, P.O. Box 3838, Socorro, NM 87801.