[1] Univ Naples Federico II, Dept Struct Engn & Architecture, Naples, Italy
[2] Univ Basilicata, Sch Engn, Potenza, Italy
[3] Sapienza Univ Rome, Dept Struct & Geotech Engn, Rome, Italy
[4] Univ G dAnnunzio, Dept Engn & Geol, Viale Pindaro 42, I-65127 Pescara, Italy
[5] Willis Grp Ltd, Willis Re, London, England
[6] Univ Ljubljana, Fac Civil & Geodet Engn, Ljubljana, Slovenia