Nonstationary response of orthotropic bridge deck to moving vehicle

Abstract

In the present paper, an orthotropic bridge deck has been analyzed to find out non-stationary response statistics when subject to moving vehicle at variable velocity. The solution strategy adopted is Monte Carlo simulation technique after properly developing system equations and dynamic excitation. The governing partial differential equation of the orthotropic plate is first discretized using mode superimposition technique and then combined with equation of motions of the rigid vehicle model. Exact mode shape functions and natural frequencies are used in the discretization of the equations of motion. Bridge deck roughness has been modeled by generalized power spectral density (PSD) function. As the vehicle traverses with variable velocity over the uneven surface, the wheel input becomes nonstationary which renders the second order statistics of the bridge dynamic response, a time dependent stochastic process. The response statistics of the mid span displacement have been presented and effects of vehicle speed/acceleration on the dynamic amplification factors (DAF) are discussed.