Strength in operation of gas pipelines in the Far North

Abstract

1. The principal cause of breakdown of gas pipes above ground in the Far North are fatigue cracks in the zone where the pipe lies on supports, caused by the effect of wind. 2. The vibrations of a multispan pipe under the effect of wind load may attain resonance values, because in the process of operation it may happen that under the effect of variable temperatures and settling and distention of the pile piers, the pipe does not lie on some of the supports; this increases the length of the spans. 3. The mechanical properties of the metal of the pipes after lengthy operation remain at a level satisfying the requirements of the Far North. 4. When gas pipelines above ground are designed, calculation of fatigue has to take into account the random nature of the wind load and the fatigue properties of the pipe steels and of the welded joints.