1. Prof. of Civ. Engrg., Univ. of California, Berkeley, Calif.
2. Prof. of Civ. Engrg., Massachusetts Institute of Technology, Cambridge, Mass.
3. Asst. Prof. of Civ. Engrg., Univ. of Tehran, Tehran, Iran
4. Research Assoc., Dept. of Civ. Engrg., Massachusetts Institute of Technology, Cambridge, Mass.
5. Asst. Research Engr., Univ. of California, Berkeley, Cahf., and ProJect Engr., Woodward-Lundgren & Assoc., Oakland, Calif.