In recent years, the size, number, and applications of offshore pipelines have been steadily increasing. The design and construction of pipelines in offshore cold regions calls for special measures (such as deep burial) because of seabed scouring caused by ice.Various societies and associations have pointed out the deficiencies in the state-of-the-art areas of environmental, design, and construction factors, particularly those dealing with structural, external pressure effects, and depth of burial. It has also been recommended that more data be obtained in order to fully evaluate pipeline–soil interaction. Also, field measurements of velocities, accelerations, and forces causing scour around pipelines would greatly enhance our understanding of offshore pipeline behavior.Offshore pipelines fail in many different ways, and each mode of failure should be examined individually. Because of the complexity of the ocean environment it is quite difficult to evaluate pipeline failures in detail.Environmental factors such as hydrodynamic wave forces and currents, buoyancy forces due to liquefaction of sediment, and scouring potential are presented. The dynamics of scour, incipient sediment motion, depth of scour, and scour patterns around pipelines are also reviewed as well as the maximum scour depths as a function of bottom current velocity.Methods for scour protection in shallow and deep water are described as well as the need for inspection and maintenance to prevent failures. Key words: pipelines, offshore, hydrodynamic forces, cover, scour.
