Wave induced random oscillations of pipelines during laying

Abstract A study is presented of wave induced random vibrations of pipelines suspended in the J- configuration . The analysis is based on the use of Morison's equation for the hydrodynamic forces and a linearized spectral analysis of response in the first five normal modes of oscillation. Three pipelines are studied for an operational sea state of H S = 4.57 m and a survival case of H S = 12 m . Extensive results are given for the expected peak deflections and stresses. Under operational conditions the expected peak stresses were found to be well below the maximum allowable stress for both the pipeline and the concrete coating, but in the survival case the peak stresses were found to be unacceptably high.