1. Assistant Professor, Dept. of Structural Engineering, Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133 Milan, Italy. E-mail: palermo@polimi.it
2. Senior Lecturer, Dept. of Civil Engineering, Univ. of Canterbury, Private Bag 4800, 8020 Christchurch, New Zealand (corresponding author). E-mail: stefano.pampanin@canterbury.ac.nz
3. Ph.D. Candidate, Dept. of Civil Engineering, Univ. of Canterbury, Private Bag 4800, 8020 Christchurch, New Zealand. E-mail: djm178@student.canterbury.ac.nz