1. Associate Professor, Dept. of Civil Engineering, Middle East Technical Univ., 06531 Ankara, Turkey.
2. Professor, Dept. of Civil and Environmental Engineering, Brigham Young Univ., Provo, UT 84602.
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of California at Berkeley, Berkeley, CA 94720.
4. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of California, Los Angeles, CA 90095.
5. Professor, Dept. of Civil Engineering, Bogazici Univ., 80815 Bebek, Istanbul, Turkey.
6. William Lettis and Associates, Inc., Walnut Creek, CA 94596.
7. Graduate Student Researcher, Dept. of Civil Engineering, Middle East Technical Univ., 06531 Ankara, Turkey.