Modal identification of a cable-stayed bridge by means of truck induced vibrations

Abstract

This paper presents the results of a field testing campaign performed on the Adige bridge, a highway cable-stayed bridge located 70 km southeast of Verona, in the north of Italy. The structure has an overall length of 580 m and a main span of 310 m and is currently the longest cable-stayed bridge in Italy. The dynamic tests described were conducted before the bridge opening to the traffic. In order to excite the bridge a 40000 kg truck was run at several constant speeds on a series of rectangular obstacles equally spaced along one of the bridge lanes. The dynamic response of the bridge deck was measured through servo-accelerometers. The position of the accelerometers along the bridge, the distance between the obstacles and the vehicle speeds were selected on the basis of a 3D Finite Element model of the structure. The bridge modal parameters were extracted applying the least square complex exponential method (LSCE) to the free decay time histories obtained through the random decrement technique (RDT) and were compared with the ones of the FE model. © The Society for Experimental Mechanics, Inc. 2012.