1. Researcher, Dept. of CEAE, Univ. of Colorado, Boulder, CO 80309-0428; also, Facolta’ di Architettura, Univ. “G. D’Annunzio” di Chieti-Pescara, viale Pindaro 42, 65127 Pescara, Italy.
2. Professor, Dept. of Structural Engineering, Univ. of California, San Diego, CA 92093.