Influences of the Material Properties of Cement Asphalt Mortar on Box Bridge Structure Vibration-Born Noise

Due to growing concerns on the low-frequency box bridge structure vibration-born noise, the noise and vibration reduction design becomes a research focus at present. In this paper, based on the slab ballastless track- box bridge coupling dynamic model developed by the finite element method, the influences of stiffness and damping of the cement asphalt mortar (CAM) layer on the elevated box bridge structure vibration and noise radiation are studied. The results show that: the effect of stiffness of the CAM layer on the sound pressure level (SPL) caused by the box bridge structure vibration is not obvious, but the radiation scope of the box bridge structure noise is expanded by the greater stiffness of the CAM layer; with the damping of CAM layer increasing, the sound pressure of vertical acoustic field decreases, and the radiation scopes above and below the box bridge are also smaller, but the sound pressures of the noise concentration areas near the box bridge increases.