1. Institute of Structural Analysis and Dynamics of Structures, Department of Civil Engineering; Aristotle University of Thessaloniki; Panepistimioupolis Mail Stop 502 Thessaloniki 54124 Greece
2. Institute of Structural Engineering; Department of Civil, Environmental and Geomatic Engineering; ETH Zürich, Stefano-Franscini-Platz 5 CH-8093 Zürich Switzerland
3. Research Unit in Engineering Science; Luxembourg University; 6 rue Richard Coudenhove-Kalergi Luxembourg City L-1359 Luxembourg
4. Institute of Theoretical, Applied and Computational Mechanics; Cardiff University; Cardiff CF24 3AA UK