Impedance Model of Train-Induced Vibration Transmission Across a Transfer Structure into an Overtrack Building in a Metro Depot

AbstractIn recent years, the construction of the overtrack building complexes including offices, schools, residences, stores, and restaurants above metro depots has increased in China. Train-generated vibration transmits through ground columns into and across transfer structures into the building’s columns and upper floors. The vibration has the potential to impact people’s quality of life, work in office buildings, and the proper function of vibration-sensitive equipment in laboratories. An efficient computational model has been developed that characterizes the dominant mode of vibration transmission through each structural element including those in transfer structures in building designs where ground and building columns are not aligned. Impedance matrices are combined for the elements along the transmission path from inputs at ground columns with axial wave transmission into the transfer structures’ girders and beams with bending wave transmission and the building columns with axial wave transmission. Floors are characterized by point input impedances. Model inputs are vibration levels at ground column bases during train pass-bys. Model predictions were compared with measured vibration levels within a 4-story overtrack building on a transfer structure in the Qianhai depot in China. The agreement between predicted and measured vibration levels was quite good. The proposed model can be used to accurately predict overtrack vibration levels for buildings supported on a transfer structure with a small computational cost in order to identify potential vibration concerns prior to construction.