1. Postdoctoral Fellow, Dept. of Civil, Architectural, and Environmental Engineering, Missouri Univ. of Science and Technology, 1870 Miner Circle, Rolla, MO 65409.
2. Distinguished Professor, Dept. of Civil, Architectural, and Environmental Engineering, Missouri Univ. of Science and Technology, 1870 Miner Circle, Rolla, MO 65409 (corresponding author).