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In order to investigate the acoustic vibration characteristics of steel-concrete composite (SCC) beams under train excitation, a 50 m simply supported SCC beam on a high-speed railway with a train speed of 400 km/h was taken as the subject. The acoustic vibration responses of the bridge under vehicle load were calculated using a hybrid Finite Element-Boundary Element-Statistical Energy Analysis (FE- BE-SEA) prediction method. The results were compared with those of a concrete simply supported box beam of similar span under the same excitation conditions. The effects of track parameters (such as damping pads) and structural parameters (including deck thickness and diaphragm spacing) on the vibration and acoustic radiation characteristics of the bridge were studied. The results showed that, among the components of the steel-concrete composite beam, the deck exhibited the highest total vibration acceleration level. In most frequency bands, compared with SCC, the vibration and sound responses of concrete beam were significantly lower, with the vibration responses of the concrete web being reduced the most. The damping pads were found to be highly effective in vibration reduction and noise attenuation, particularly in the mid-to-high frequency ranges. Changing the thickness of the bridge deck reduced the structural noise of the SCC. When the deck thickness increased by 50%, the total sound pressure levels (SPLs) of the structural noise changed by -3.0 dB(A) to -2.9 dB(A). Reducing the diaphragm spacing also significantly reduced the structural noise of the bridge. When the diaphragm spacing was reduced by 50%, the total SPLs changed by -5.6 dB(A) to -5.0 dB(A). [ABSTRACT FROM AUTHOR]

Due to advantages such as small weight, large load capacity, and easy manufacturing, orthotropic steel decks (OSDs) are widely used in many steel bridges. As an important component of steel bridge decks that bear vehicle loads, OSDs may produce excessive vibrations and corresponding noise due to low dead loads. Therefore, it is important to study the vibration behavior of OSDs to guide the design to reduce vibration and noise in steel bridges. In this paper, the vibration response of an OSD with simply supported boundary conditions is calculated using the modal expansion method. The input mobility and insertion loss are selected as indices to evaluate the vibration response and suppression performance of the bridge. The results of calculations were compared with those of the finite element method to verify their accuracy. They showed that the input mobility of the OSD was affected primarily by the bending stiffness of the corresponding top plate and longitudinal ribs. The vibration energy of the OSD had both frequency-dependent and excitation location-dependent characteristics. When a source acted on the longitudinal rib or was close to it (within a distance of ¼ of the wavelength), the high-frequency vibration response of the OSD could still be greatly suppressed, with an average vibration reduction of approximately 15 dB. Reducing the spacing between the longitudinal ribs is one of the best ways to reduce the vibration response of the OSD. The frequency of the positive insertion loss ranged from 160 to 500 Hz when the longitudinal rib spacing was reduced from 0.8 to 0.4 m. The frequency-related vibration response of the OSD can be further reduced by adding transverse ribs, especially in the high-frequency range. [ABSTRACT FROM AUTHOR]

To effectively and efficiently control vibrations in steel bridge decks, the flexural wave band gap and vibration attenuation mechanism are studied. The band structures and displacement fields of the eigenmodes at the band gap edges of infinite periodic U-rib stiffened plates are calculated. The calculation method is combining the finite element method with Bloch periodic boundary conditions. A scaled specimen test of a finite periodic U-rib stiffened plate is used to validate the numerical results. A comparison of results confirms that introducing the U-rib allows the periodic U-rib stiffened plates to yield several flexural wave band gaps. In the band gaps, flexural wave propagation is stopped and clear flexural vibration suppression is achieved. Furthermore, the effects of geometric parameters and structural schemes on the flexural wave band gaps are analyzed in detail. Finally, by analyzing a specific case, it is demonstrated that the flexural wave band gaps and vibration attenuation properties can be controlled. This provides a new approach to vibration and noise control in steel bridges. [ABSTRACT FROM AUTHOR]