# Vibration Response Analysis of Overhead System Regarding Train-Track-Bridge Dynamic Interaction
###### Abstract
[PERSON] [10] developed a dynamic analysis model for the spatial coupling system of a high-speed train ballast-less track bridge based on the construction background of Guangzhou Zhuhai railway's Xi Jiang extra-large continuous beam bridge and performed a vibration simulation analysis of the train track bridge system, with track irregularity serving as a vibration excitation source. The dynamic responses of trains and bridges at various speeds and track irregularity levels are calculated, and a preliminary discussion of the relationship between dynamic response values and train speed and track irregularity levels is conducted. Based on nonlinear Hertz contact theory, [PERSON] [11] developed a finite element model of train track bridge vertical vibration, derived the rail bridge coupling element of arbitrary length combination, and investigated the impact of track and bridge element length. The findings indicate that using a larger bridge element and improving the track element can achieve the required accuracy and efficiency and that the length of the track element affects the calculation's outcome. There must be a minimum of two-track units per minimum train wheelbase. [PERSON] [12] and [PERSON] [13] divided the train bridge system into two subsystems, established train and bridge motion equations for each, and connected them through wheel-rail interaction to study the vibration response of a truss bridge under train action. This model has been widely adopted and applied by researchers worldwide, having a significant impact on modern train bridge vibration theory. [PERSON] [14] used numerical analysis techniques and track irregularity samples as systematic excitation to investigate the dynamic performance of a large steel truss arch bridge and track under train operation. The findings show that the train track bridge dynamic interaction theory can be used to assess and evaluate the dynamic behavior of complex bridge structures in actual high-speed railway engineering. It is clear from the published works that the theory and method of train-track-bridge interaction have been gradually perfected. The theoretical investigation establishes a research foundation for the vibration response of train-track-bridge interaction to bridge structure and train. However, there are still some gaps in the study of dynamic characteristics of temporary structure railway line reinforcement systems under train-track-bridge coupling during construction in terms of coupled response. This paper takes the Longhai railway overpass project on Jingjiu road as an example, with the overpass project adopting the structural form of a framed underpass. To ensure the safety of the upper and lower structures during the construction of the underpass bridge structure, it is necessary to study the dynamic performance of the overhead system of the superstructure. This paper combines MIDAS/civil software, ABAQUS finite element software, and multi-body dynamics software Universal Mechanism (UM), analyzes the vibration response of the overhead system under the coupling effect of the vehicle track overhead system, and investigates the impact of track irregularity, train speed and bridge damping coefficient on the dynamic response of the train track overhead system to provide a new modeling idea for the research of train-track -bridge systems, guiding the design of this type of structure, and guaranteeing the structural safety.