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摘要
The traditional operational modal identification involves a large number of sensors and is unable to obtain the mass-normalized mode shape, while the Moving Vehiele Seanning Method with limited sensors is usually too sensitive to the irregularity of road surfaee anil difficult to mass-normalize the mode shape. A bridge modal identification method (for frequency and mass-normalized mode shape) that is insensitive to road surface irregularity by using a small number of sensors is proposed. In this method, the vehicle is parked on a selected position to form a parked vehicle-bridge system anil the corresponding frequency is estimated. Then the vehicle is moved to the nex.t position and the test procedure is repeated, and so on. The modal parameters are identified via measuring a series of parked vehicle-bridge systems, and thus it is named the Parked Vehicle based Bridge Modal Identification Method . Firstly, numerical examples are used to demonstrate the phenomenon that the frequencies of the parked vehicle-bridge systems change with the position of the parked vehiele. Secondly, the physical relationship between the frequency variation of the parked vehicle-bridge system and the bridge modal parameters is revealed through theoretical derivation, and the modal identification theory is established accordingly. Then the modal identification procedures by measuring a series of frequencies of the parked vehicle-bridge systems is provided and verified. Finally, the influences of vehicle/bridge mass ratio and vehicle stiffness on the identification results are investigated systematically. The results indicate that the mode shape identification is transformed into frequency identification, and the mass-normalized mode shape of bridge can lie quickly identified with only a small number of acceleration sensors. ? 2023 Editorial Office of China Civil Engineering Journal.
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