1. Assistant Professor, Dept. of Civil Engineering, Boaziçi Univ., Bebek 80815, Istanbul, Turkey.
2. Professor, Dept. of Civil Engineering and Engineering Mechanics, Columbia Univ., New York, NY 10027.
3. Graduate Student, Dept. of Civil Engineering and Engineering Mechanics, Columbia Univ., New York, NY 10027.
4. Assistant Professor, Dipartimento Ingegneria Strutturale e Geotecnica, Univ. di Roma “La Sapienza,” Rome, Italy.