Vibration of Suspension Pipeline Bridge Subjected to Process of Pigging

This paper presents a study on the vibration of a suspension pipeline bridge subjected to moving pig. The structure is modeled as a single-span beam suspended by cables. The pig and the liquid in front of it are simulated as a sequence of equidistant moving loads with identical weight. The governing equation of motion is discretized by Newmark´s method and then solved by a rigorous incremental-iterative procedure that takes into account the nonlinear effects. The results indicate that once the exciting passage frequency coincides with natural frequencies, resonance will be developed on the bridge. With regard to this pipeline bridge we should avoid the speed of 2m/s, 4m/s. For the oil pipeline, the oil full filled in the pipe is beneficial for mitigating the pig induced acceleration. For the gas pipeline, the vibration is obvious especially when l (liquid length) is 8m. The dynamic displacement changes over time provide intuitively basis for vibration forecast and suppression control.