[1] Univ Basilicata, Sch Engn, Via Ateneo Lucano 10, I-85100 Potenza, Italy
[2] Univ Sannio, Dept Engn, Piazza Roma 21, I-80121 Benevento, Italy
[3] Univ Canterbury, Dept Civil & Nat Resources Engn, Private Bag 4800, Christchurch, New Zealand
[4] Univ Naples Federico II, Dept Struct Engn, Via Claudio 21, I-80125 Naples, Italy
[5] Univ G DAnnunzio, Dipartimento Ingn & Geol, Viale Pindaro 42, I-65127 Pescara, Italy