FINITE-ELEMENT STRESS-ANALYSIS OF UNILATERALLY SUPPORTED SUBMARINE PIPELINES

A linear-elastic finite element model is applied to the solution of st ress analysis problems involving submarine pipelines freely resting up on irregular seabed profiles. The structural matrix system is derived on an equal length element assembly basis, thus enabling the formulati on of a particularly compact 3 d.f nodal equation algorithm. The unkno wn contact points and the pipeline deformations are simultaneously ide ntified with the aid of a successive over-relaxation solution algorith m. Tensions generated due to mean internal and external fluid pressure differences are taken into account. Surcharge imposition proves benef icial for the control of critical pipeline over-stressing and upward l ift during pressurization. Case study details of the installation desi gn for a subsea dual pipeline crossing are included. A FORTRAN subrout ine is provided for illustration purposes of the proposed numerical te chnique. Copyright (C) 1996 Elsevier Science Ltd.