1. Associate Professor, University of Messina, Department of Engineering, C.da di Dio, 98166 S. Agata (ME), Italy
2. Associate Professor, University of Catania, Department of Civil Engineering and Architecture,v.le A, Doria, 6, 95125 Catania, Italy
3. Assistant Professor, University of Catania, Department of Civil Engineering and Architecture,v.le A, Doria, 6, 95125 Catania, Italy
4. Full Professor, University of Catania, Department of Civil Engineering and Architecture,v.le A, Doria, 6, 95125 Catania, Italy