Modal analysis of a coupled ballastless railway track surrounding a horse shoe shape shield tunnel linked to a box-girder bridge with substructure using finite element method

Examining the modal analysis of an integrated structure consisting of a box-girder bridge and a tunnel with a railroad track is critical for ensuring structural integrity, safety, and functionality, especially concerning resonance with time-varying external forces such as vehicle and seismic loads. Prior studies have indicated that modal analysis of this kind of integrated system has received little attention. The key objective of this research is to determine the natural frequency and mode shape of this integrated system. The free vibration analysis of the FEM model of the integrated system is carried out by the FEM software, ANSYS. The modal character parameters of the present model are investigated by comparing free vibration analysis with and without a railway track. The natural frequencies of this model without the railway track system were reduced as an outcome of a decrease in model stiffness.