A pipeline constructor asked to check and validate the design of PU spacers protecting a 3LPE (3-layer polyethylene) coating during the pulling of a pipeline section through a concrete tunnel.
The question was raised under which condition of weather and leg height, resonance of a jack-up barge could occur. A safe operational window to avoid lock-in of the legs was identified and critical conditions have been determined.
The stability of subsea pipelines, marine risers and offshore structures can be compromised by fluid-structure interaction. Vortex induced vibrations lead to fatigue of flow lines under free span and risers. It was possible to determine the loading pattern and compare it to the pipeline’s characteristics.