Offshore Installation of Reinforced Thermoplastic Pipe (RTP)

This paper aims to study the installation of Reinforced Thermoplastic Pipe (RTP) in offshore applications. RTP is a flexible pipe which consists of a thermoplastic liner, two-layer reinforcement and a thermoplastic protective outer covering. Thus it can be supplied on long-length coils and installed quickly. Due to RTP’s unique construction, behaviors under axial loading and bending loading are analyzed in advance. A theoretical model is proposed to deal with the configuration and internal loads along the pipeline during the laying process. The total pipeline configuration from the lay-barge to the seabed is divided into two parts: one part suspended in water, the other part laid on the seabed. The effect of seabed stiffness is considered in the model. The continuity of the two parts at touch down point (TDP) is applied as the control condition to get the reliable top tension. A numerical iteration program based on the model is developed to get the pipeline configuration, axial tension and bending moment distribution. The results from the theoretical model show good agreement with the finite element model using ABAQUS.