[1] Univ Naples Federico II, Dept Struct Engn & Architecture, Via Claudio 25, I-80121 Naples, Italy
[2] Univ Salerno, Dept Civil Engn, I-84084 Fisciano, SA, Italy
[3] Univ Cassino, Dept Civil & Mech Engn, Via G Di Biasio 43, I-03043 Cassino, Italy
[4] Southern Lazio, Via G Di Biasio 43, I-03043 Cassino, Italy