1. Faculty of Civil Engineering and Geosciences, Department of Structural Engineering, Delft University of Technology, Stevinweg 1, Delft 2628CN, The Netherlands; TNO Structural Dynamics, Leeghwaterstraat 44, Delft 2628CA, The Netherlands e-mail:
2. Faculty of Civil Engineering and Geosciences, Department of Structural Engineering, Delft University of Technology, Stevinweg 1, Delft 2628CN, The Netherlands e-mail: