Postbuckling Analysis of Snaked-Lay Pipelines Based on a New Deformation Shape

Lateral buckling must be considered in exposed HP/HT pipeline design. The snaked-lay method is an effective lateral buckling control method, a new deformation shape of snaked-lay pipeline is presented, and a control criterion of offset angle is also presented. When the offset angle is small or offset angle is large while the pipeline length of snaked-lay is too short or long, the maximum moments of postbuckling pipeline are large. For these problems, a new controlling method combined with snaked-lay and sleeper is proposed, which is named the SS method. Using Ansys, a nonlinear finite element model considering the interaction of seabed-sleeper-pipeline is established. The SS method is proved to be feasible to control lateral buckling for submarine pipelines. Based on critical axial compressive force and maximum bending moment, a design criterion of sleeper height is suggested.