| dc.description.abstract | The Nanfang′ao Bridge suddenly collapsed on the morning of October 1, 2018, highlighting the importance of bridge safety maintenance. The Guandu Bridge is currently over 40 years old, and the serviceability and safety of the bridge may be questionable under the following circumstances. The research conducts numerical simulations on the bridge structure and cables.
The literature review includes the cable force calculation method, the structure of the cable and its material properties for subsequent modeling and numerical verification.
The first part of the cable force analysis is the bending stiffness analysis, which simulates the bending stiffness of the cable after being subjected to bending moments at different angles. Finally, the average value is compiled and the results are used for subsequent simulations; the second part is the study of the frequency response of each component of the cable. The cable model is divided into 4 types, and the frequency differences under different models are compared to determine the simplification method of the cable in the subsequent full-bridge model.
The full bridge analysis establishes a numerical model based on the as-built drawings of the Guandu Bridge. The process includes using Solid Works to create the appearance, Hyper Mesh to cut out the mesh elements, and Ls-Dyna to input the definition of materials, structural components, and boundary condition settings. The analysis includes modal analysis, static load analysis, temperature analysis, and seismic force analysis. Modal analysis preliminarily confirms whether the model is correct and obtains the natural modal frequency of Guandu Bridge. In the static load analysis, the analysis without applied cable force is first simulated, and the cable force caused by the gravity deformation of the bridge arch and main beam is obtained, and compared with the monitoring data to judge the correctness of the monitoring data; then the cable force is simulated for the simulation. Force analysis, the model is adjusted with the monitoring cable force as the target cable force, and the influence of the current monitoring cable force and gravity on the bridge deformation is simulated. The concept of temperature analysis is to exclude the influence of vehicle temperature on the monitoring cable force. Therefore, the monitoring data in the early morning period are taken, and then the relatively high and low temperature data are taken from this part of the data to compare the impact of temperature on the actual monitoring, and then in the model The temperature corresponding to the data is compared to see whether the data simulated by the finite element model corresponds to the monitoring data. | en_US |