An analytical investigation into the vibration behavior of an orthotropic steel deck

Abstract

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.