Dynamic Responses of a Four-Span Continuous Plate Structure Subjected to Moving Cars With Time-Varying Speeds

Abstract

This paper presents an experimental and theoretical study of vibration of a four-span continuous plate with two rails on top and four extra supports excited by one or two moving model cars, which is meant to represent vehicle–track–bridge dynamic interaction. Measured natural frequencies of the plate structure are used to update the finite element (FE) model of the structure. Four laser displacement transducers are placed on the ground to measure the displacements of the plate. A laser-Doppler vibrometer is used to measure the real-time speed of the moving cars, which reveals that the speeds decrease with time at a small and almost constant deceleration which can affect the structural dynamic response. A fascinating experiment is the use of two cars connected in series, which is very rare and has never been done on a multispan structure. Vibration of the plate structure excited by two moving cars separated at a distance is also measured and exhibits interesting dynamic behavior too. A theoretical model of the whole structure is constructed and an iterative method is developed to determine the dynamic response. The numerical and the experimental results are found to agree very well, in particular when deceleration is considered in the theoretical model.