1. Postdoctoral Research Associate, Dept. of Civil Engineering, Case Western Reserve Univ., Cleveland, OH 44106.
2. Technology Development Engineer, Pile Dynamics, Inc., 30725 Aurora Rd., Cleveland, OH 44139.
3. Professor, Dept. of Civil Engineering, Dept. of Electrical Engineering and Computer Science, and Dept. of Mechanical and Aerospace Engineering, Case Western Reserve Univ., Cleveland, OH 44106 (corresponding author).