1. Dept. of Structural, Geotechnical and Building Engineering, Politecnico di Torino, C.so Duca degli Abruzzi, 24, I-10129 Torino, Italy.
2. Dept. of Structural, Geotechnical and Building Engineering, Politecnico di Torino, C.so Duca degli Abruzzi, 24, I-10129 Torino, Italy (corresponding author).