1. Graduate Research Student, Dept. of Civil, Architectural and Environmental Engineering, Missouri Univ. of Science and Technology, 1304 Pine St., 201 Pine Bldg., Rolla, MO 65409.
2. Professor, Dept. of Civil, Architecture and Environment Engineering, Missouri Univ. of Science and Technology, 325 Butler-Carlton Civil Engineering Hall, 1401 North Pine St., Rolla, MO 65409 (corresponding author).