[1] Tongji Univ, Coll Civil Engn, State Key Lab Disaster Reduct Civil Engn, Siping Rd, Shanghai 200092, Peoples R China
[2] Univ Palermo, Dipartimento Ingn, Viale Sci, I-90128 Palermo, Italy
[3] Univ Liverpool, Dept Math Sci, Liverpool L69 7ZL, Merseyside, England