1. Member, ASCE
2. Assoc. Prof., Dept. of Struct. Engrg., Politecnico di Milano, piazza L. da Vinci 32, 20133 Milan, Italy. E-mail: parisi@stru.polimi.it
3. Assoc. Prof., Dept. of Mech. and Struct. Engrg., Univ. of Trento, via Mesiano 77, 38050 Trento, Italy.