1. Professor, Dept. of Civil Engineering, Case Western Reserve Univ., 10900 Euclid Ave., Cleveland, OH 44106-7201 (corresponding author).
2. Graduate Research Assistant, Dept. of Civil Engineering, Case Western Reserve Univ., 10900 Euclid Ave., Cleveland, OH 44106-7201.
3. Research Scientist, NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, OH 44135.