Dynamic analysis of submarine pipelines

The dynamic behaviour of submarine pipelines depends on the buoyancy, wave and current effects. Before analysing dynamically such pipes, their stabilization against sea bottom soil, external and internal flow, artificial weights and physical characteristics of pipe should be especially ensured. In this study, the submerged pipes are balanced to the excited forces in marine environment.The dynamic analysis of submarine pipelines are performed as method on influence lines of moving loads, elaso-kinetic approach and Finite Element Method (FEM) including Time History study. First of all, wave propagating on the submerged pipe system is applied to continuous beam system on artificial supports. According to the changing wave directions, moving wave loads on pipe for each direction are uniformly distributed. Influence lines of continuous beam system are seperately drawn for the moment and shear force of each critical section of pipe system. Maximum moment and shear force on pipe are calculated as method on influence lines. As second case, a single moving load propagating on beam causes the vertical displacement on any section of beam. Several resultant forces equivalent to the uniform distributed wave loads expose several displacements. The combination of these displacements is considered as the resultant displacement at the considered section. It is known that the moment and shear forces on beam are obtained from the derivations of these displacements. As third case, the similar displacements, moments and shear forces are calculated by the FEM using the Time History study.As a conclusion, the resulting forces and displacements of continuous beam system considered as the mentioned methods are compared. The magnitudes of resulting forces from these three cases are discussed .