1. Postdoctoral Researcher, Dept. of Civil Engineering, Washington Univ., St. Louis, MO 63130.
2. Professor and Chairman, Dept. of Civil Engineering, Washington Univ., St. Louis, MO 63130.
3. Professor, Dept. of Civil Engineering, Washington Univ., St. Louis, MO 63130.
4. Associate Professor, Dept. of Civil Engineering, Univ. of Western Ontario, London ON, Canada N6A 5B9.