Modal Frequency Shifts Measured on Xinjiang Bridge Excited by Traveling Vehicles

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Detail(s)

Original languageEnglish
Article number2650036
Journal / PublicationInternational Journal of Structural Stability and Dynamics
Online published6 Nov 2024
Publication statusOnline published - 6 Nov 2024

Abstract

To excite sufficient vibrations of bridges for more effective modal experiments to take place, traveling vehicles were utilized in many bridge field inspection campaigns in history. However, the dynamics of a bridge subjected to the traveling vehicles are of changed resonant properties compared with those of the same structure with the ambient excitation in nature. Therefore, the field modal experiments employing vehicle excitations might unfavorably lead to shifted measurement results of low-order natural frequencies for long-span bridges of large mass. Using Xinjiang Bridge (a single-tower pre-stressed concrete cable-stayed bridge with spans 40m + 150m + 150m + 40m) as the engineering background, this paper validates this technical notion based on reliable physical experiments and numerical simulations and seeks a practical approach to deal with the issue. It is found that the maximum deviation between the low-order modal frequencies measured on Xinjiang Bridge for the vehicle excitation case and those measured for the ambient excitation case (the accurate values) reaches 0.65Hz, and the deviation between the lower limit of the usual vehicle excitation's energy band and the modal frequency measured (factor 1) and the traveling vehicles' speed (factor 2) are the two key factors influencing the modal frequency shifts. An empirical model to compensate for modal frequencies' deviations is formulated considering the two key factors accordingly, which is of high-practical significance in future applications of the modal experiments using vehicle excitations to other long-span bridges. © 2026 World Scientific Publishing Company.

Research Area(s)

  • Cable-stayed bridge, frequency shift, manual tuning, modal analysis, modal experiment, vehicle excitation